preproc.c

/* -*- mode: c; c-file-style: "bsd" -*- */
/* preproc.c   macro preprocessor for the Netwide Assembler
 *
 * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
 * Julian Hall. All rights reserved. The software is
 * redistributable under the licence given in the file "Licence"
 * distributed in the NASM archive.
 *
 * initial version 18/iii/97 by Simon Tatham
 */

/* Typical flow of text through preproc
 *
 * pp_getline gets tokenized lines, either
 *
 *   from a macro expansion
 *
 * or
 *   {
 *   read_line  gets raw text from stdmacpos, or predef, or current input file
 *   tokenize   converts to tokens
 *   }
 *
 * expand_mmac_params is used to expand %1 etc., unless a macro is being
 * defined or a false conditional is being processed
 * (%0, %1, %+1, %-1, %%foo
 *
 * do_directive checks for directives
 *
 * expand_smacro is used to expand single line macros
 *
 * expand_mmacro is used to expand multi-line macros
 *
 * detoken is used to convert the line back to text
 */

#include "compiler.h"

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include <inttypes.h>

#include "nasm.h"
#include "nasmlib.h"
#include "preproc.h"
#include "hashtbl.h"

typedef struct SMacro SMacro;
typedef struct MMacro MMacro;
typedef struct Context Context;
typedef struct Token Token;
typedef struct Blocks Blocks;
typedef struct Line Line;
typedef struct Include Include;
typedef struct Cond Cond;
typedef struct IncPath IncPath;

/*
 * Note on the storage of both SMacro and MMacros: the hash table
 * indexes them case-insensitively, and we then have to go through a
 * linked list of potential case aliases (and, for MMacros, parameter
 * ranges); this is to preserve the matching semantics of the earlier
 * code.  If the number of case aliases for a specific macro is a
 * performance issue, you may want to reconsider your coding style.
 */

/*
 * Store the definition of a single-line macro.
 */
struct SMacro {
    SMacro *next;
    char *name;
    bool casesense;
    int in_progress;
    unsigned int nparam;
    Token *expansion;
};

/*
 * Store the definition of a multi-line macro. This is also used to
 * store the interiors of `%rep...%endrep' blocks, which are
 * effectively self-re-invoking multi-line macros which simply
 * don't have a name or bother to appear in the hash tables. %rep
 * blocks are signified by having a NULL `name' field.
 *
 * In a MMacro describing a `%rep' block, the `in_progress' field
 * isn't merely boolean, but gives the number of repeats left to
 * run.
 *
 * The `next' field is used for storing MMacros in hash tables; the
 * `next_active' field is for stacking them on istk entries.
 *
 * When a MMacro is being expanded, `params', `iline', `nparam',
 * `paramlen', `rotate' and `unique' are local to the invocation.
 */
struct MMacro {
    MMacro *next;
    char *name;
    int nparam_min, nparam_max;
    bool casesense;
    bool plus;                   /* is the last parameter greedy? */
    bool nolist;                 /* is this macro listing-inhibited? */
    int in_progress;
    Token *dlist;               /* All defaults as one list */
    Token **defaults;           /* Parameter default pointers */
    int ndefs;                  /* number of default parameters */
    Line *expansion;

    MMacro *next_active;
    MMacro *rep_nest;           /* used for nesting %rep */
    Token **params;             /* actual parameters */
    Token *iline;               /* invocation line */
    unsigned int nparam, rotate;
    int *paramlen;
    uint32_t unique;
    int lineno;                 /* Current line number on expansion */
};

/*
 * The context stack is composed of a linked list of these.
 */
struct Context {
    Context *next;
    SMacro *localmac;
    char *name;
    uint32_t number;
};

/*
 * This is the internal form which we break input lines up into.
 * Typically stored in linked lists.
 *
 * Note that `type' serves a double meaning: TOK_SMAC_PARAM is not
 * necessarily used as-is, but is intended to denote the number of
 * the substituted parameter. So in the definition
 *
 *     %define a(x,y) ( (x) & ~(y) )
 * 
 * the token representing `x' will have its type changed to
 * TOK_SMAC_PARAM, but the one representing `y' will be
 * TOK_SMAC_PARAM+1.
 *
 * TOK_INTERNAL_STRING is a dirty hack: it's a single string token
 * which doesn't need quotes around it. Used in the pre-include
 * mechanism as an alternative to trying to find a sensible type of
 * quote to use on the filename we were passed.
 */
enum pp_token_type {
    TOK_NONE = 0, TOK_WHITESPACE, TOK_COMMENT, TOK_ID,
    TOK_PREPROC_ID, TOK_STRING,
    TOK_NUMBER, TOK_SMAC_END, TOK_OTHER, TOK_SMAC_PARAM,
    TOK_INTERNAL_STRING
};

struct Token {
    Token *next;
    char *text;
    SMacro *mac;                /* associated macro for TOK_SMAC_END */
    enum pp_token_type type;
};

/*
 * Multi-line macro definitions are stored as a linked list of
 * these, which is essentially a container to allow several linked
 * lists of Tokens.
 * 
 * Note that in this module, linked lists are treated as stacks
 * wherever possible. For this reason, Lines are _pushed_ on to the
 * `expansion' field in MMacro structures, so that the linked list,
 * if walked, would give the macro lines in reverse order; this
 * means that we can walk the list when expanding a macro, and thus
 * push the lines on to the `expansion' field in _istk_ in reverse
 * order (so that when popped back off they are in the right
 * order). It may seem cockeyed, and it relies on my design having
 * an even number of steps in, but it works...
 *
 * Some of these structures, rather than being actual lines, are
 * markers delimiting the end of the expansion of a given macro.
 * This is for use in the cycle-tracking and %rep-handling code.
 * Such structures have `finishes' non-NULL, and `first' NULL. All
 * others have `finishes' NULL, but `first' may still be NULL if
 * the line is blank.
 */
struct Line {
    Line *next;
    MMacro *finishes;
    Token *first;
};

/*
 * To handle an arbitrary level of file inclusion, we maintain a
 * stack (ie linked list) of these things.
 */
struct Include {
    Include *next;
    FILE *fp;
    Cond *conds;
    Line *expansion;
    char *fname;
    int lineno, lineinc;
    MMacro *mstk;               /* stack of active macros/reps */
};

/*
 * Include search path. This is simply a list of strings which get
 * prepended, in turn, to the name of an include file, in an
 * attempt to find the file if it's not in the current directory.
 */
struct IncPath {
    IncPath *next;
    char *path;
};

/*
 * Conditional assembly: we maintain a separate stack of these for
 * each level of file inclusion. (The only reason we keep the
 * stacks separate is to ensure that a stray `%endif' in a file
 * included from within the true branch of a `%if' won't terminate
 * it and cause confusion: instead, rightly, it'll cause an error.)
 */
struct Cond {
    Cond *next;
    int state;
};
enum {
    /*
     * These states are for use just after %if or %elif: IF_TRUE
     * means the condition has evaluated to truth so we are
     * currently emitting, whereas IF_FALSE means we are not
     * currently emitting but will start doing so if a %else comes
     * up. In these states, all directives are admissible: %elif,
     * %else and %endif. (And of course %if.)
     */
    COND_IF_TRUE, COND_IF_FALSE,
    /*
     * These states come up after a %else: ELSE_TRUE means we're
     * emitting, and ELSE_FALSE means we're not. In ELSE_* states,
     * any %elif or %else will cause an error.
     */
    COND_ELSE_TRUE, COND_ELSE_FALSE,
    /*
     * This state means that we're not emitting now, and also that
     * nothing until %endif will be emitted at all. It's for use in
     * two circumstances: (i) when we've had our moment of emission
     * and have now started seeing %elifs, and (ii) when the
     * condition construct in question is contained within a
     * non-emitting branch of a larger condition construct.
     */
    COND_NEVER
};
#define emitting(x) ( (x) == COND_IF_TRUE || (x) == COND_ELSE_TRUE )

/* 
 * These defines are used as the possible return values for do_directive
 */
#define NO_DIRECTIVE_FOUND  0
#define DIRECTIVE_FOUND	    1

/*
 * Condition codes. Note that we use c_ prefix not C_ because C_ is
 * used in nasm.h for the "real" condition codes. At _this_ level,
 * we treat CXZ and ECXZ as condition codes, albeit non-invertible
 * ones, so we need a different enum...
 */
static const char * const conditions[] = {
    "a", "ae", "b", "be", "c", "cxz", "e", "ecxz", "g", "ge", "l", "le",
    "na", "nae", "nb", "nbe", "nc", "ne", "ng", "nge", "nl", "nle", "no",
    "np", "ns", "nz", "o", "p", "pe", "po", "rcxz", "s", "z"
};
enum pp_conds {
    c_A, c_AE, c_B, c_BE, c_C, c_CXZ, c_E, c_ECXZ, c_G, c_GE, c_L, c_LE,
    c_NA, c_NAE, c_NB, c_NBE, c_NC, c_NE, c_NG, c_NGE, c_NL, c_NLE, c_NO,
    c_NP, c_NS, c_NZ, c_O, c_P, c_PE, c_PO, c_RCXZ, c_S, c_Z,
    c_none = -1
};
static const enum pp_conds inverse_ccs[] = {
    c_NA, c_NAE, c_NB, c_NBE, c_NC, -1, c_NE, -1, c_NG, c_NGE, c_NL, c_NLE,
    c_A, c_AE, c_B, c_BE, c_C, c_E, c_G, c_GE, c_L, c_LE, c_O, c_P, c_S,
    c_Z, c_NO, c_NP, c_PO, c_PE, -1, c_NS, c_NZ
};

/*
 * Directive names.
 */
/* If this is a an IF, ELIF, ELSE or ENDIF keyword */
static int is_condition(enum preproc_token arg)
{
    return PP_IS_COND(arg) || (arg == PP_ELSE) || (arg == PP_ENDIF);
}

/* For TASM compatibility we need to be able to recognise TASM compatible
 * conditional compilation directives. Using the NASM pre-processor does
 * not work, so we look for them specifically from the following list and
 * then jam in the equivalent NASM directive into the input stream.
 */

#ifndef MAX
#       define MAX(a,b) ( ((a) > (b)) ? (a) : (b))
#endif

enum {
    TM_ARG, TM_ELIF, TM_ELSE, TM_ENDIF, TM_IF, TM_IFDEF, TM_IFDIFI,
    TM_IFNDEF, TM_INCLUDE, TM_LOCAL
};

static const char * const tasm_directives[] = {
    "arg", "elif", "else", "endif", "if", "ifdef", "ifdifi",
    "ifndef", "include", "local"
};

static int StackSize = 4;
static char *StackPointer = "ebp";
static int ArgOffset = 8;
static int LocalOffset = 4;

static Context *cstk;
static Include *istk;
static IncPath *ipath = NULL;

static efunc _error;            /* Pointer to client-provided error reporting function */
static evalfunc evaluate;

static int pass;                /* HACK: pass 0 = generate dependencies only */

static uint32_t unique;    /* unique identifier numbers */

static Line *predef = NULL;

static ListGen *list;

/*
 * The current set of multi-line macros we have defined.
 */
static struct hash_table *mmacros;

/*
 * The current set of single-line macros we have defined.
 */
static struct hash_table *smacros;

/*
 * The multi-line macro we are currently defining, or the %rep
 * block we are currently reading, if any.
 */
static MMacro *defining;

/*
 * The number of macro parameters to allocate space for at a time.
 */
#define PARAM_DELTA 16

/*
 * The standard macro set: defined as `static char *stdmac[]'. Also
 * gives our position in the macro set, when we're processing it.
 */
#include "macros.c"
static const char **stdmacpos;

/*
 * The extra standard macros that come from the object format, if
 * any.
 */
static const char **extrastdmac = NULL;
bool any_extrastdmac;

/*
 * Tokens are allocated in blocks to improve speed
 */
#define TOKEN_BLOCKSIZE 4096
static Token *freeTokens = NULL;
struct Blocks {
    Blocks *next;
    void *chunk;
};

static Blocks blocks = { NULL, NULL };

/*
 * Forward declarations.
 */
static Token *expand_mmac_params(Token * tline);
static Token *expand_smacro(Token * tline);
static Token *expand_id(Token * tline);
static Context *get_ctx(char *name, bool all_contexts);
static void make_tok_num(Token * tok, int32_t val);
static void error(int severity, const char *fmt, ...);
static void *new_Block(size_t size);
static void delete_Blocks(void);
static Token *new_Token(Token * next, enum pp_token_type type, char *text, int txtlen);
static Token *delete_Token(Token * t);

/*
 * Macros for safe checking of token pointers, avoid *(NULL)
 */
#define tok_type_(x,t) ((x) && (x)->type == (t))
#define skip_white_(x) if (tok_type_((x), TOK_WHITESPACE)) (x)=(x)->next
#define tok_is_(x,v) (tok_type_((x), TOK_OTHER) && !strcmp((x)->text,(v)))
#define tok_isnt_(x,v) ((x) && ((x)->type!=TOK_OTHER || strcmp((x)->text,(v))))

/* Handle TASM specific directives, which do not contain a % in
 * front of them. We do it here because I could not find any other
 * place to do it for the moment, and it is a hack (ideally it would
 * be nice to be able to use the NASM pre-processor to do it).
 */
static char *check_tasm_directive(char *line)
{
    int32_t i, j, k, m, len;
    char *p = line, *oldline, oldchar;

    /* Skip whitespace */
    while (isspace(*p) && *p != 0)
        p++;

    /* Binary search for the directive name */
    i = -1;
    j = elements(tasm_directives);
    len = 0;
    while (!isspace(p[len]) && p[len] != 0)
        len++;
    if (len) {
        oldchar = p[len];
        p[len] = 0;
        while (j - i > 1) {
            k = (j + i) / 2;
            m = nasm_stricmp(p, tasm_directives[k]);
            if (m == 0) {
                /* We have found a directive, so jam a % in front of it
                 * so that NASM will then recognise it as one if it's own.
                 */
                p[len] = oldchar;
                len = strlen(p);
                oldline = line;
                line = nasm_malloc(len + 2);
                line[0] = '%';
                if (k == TM_IFDIFI) {
                    /* NASM does not recognise IFDIFI, so we convert it to
                     * %ifdef BOGUS. This is not used in NASM comaptible
                     * code, but does need to parse for the TASM macro
                     * package.
                     */
                    strcpy(line + 1, "ifdef BOGUS");
                } else {
                    memcpy(line + 1, p, len + 1);
                }
                nasm_free(oldline);
                return line;
            } else if (m < 0) {
                j = k;
            } else
                i = k;
        }
        p[len] = oldchar;
    }
    return line;
}

/*
 * The pre-preprocessing stage... This function translates line
 * number indications as they emerge from GNU cpp (`# lineno "file"
 * flags') into NASM preprocessor line number indications (`%line
 * lineno file').
 */
static char *prepreproc(char *line)
{
    int lineno, fnlen;
    char *fname, *oldline;

    if (line[0] == '#' && line[1] == ' ') {
        oldline = line;
        fname = oldline + 2;
        lineno = atoi(fname);
        fname += strspn(fname, "0123456789 ");
        if (*fname == '"')
            fname++;
        fnlen = strcspn(fname, "\"");
        line = nasm_malloc(20 + fnlen);
        snprintf(line, 20 + fnlen, "%%line %d %.*s", lineno, fnlen, fname);
        nasm_free(oldline);
    }
    if (tasm_compatible_mode)
        return check_tasm_directive(line);
    return line;
}

/*
 * Free a linked list of tokens.
 */
static void free_tlist(Token * list)
{
    while (list) {
        list = delete_Token(list);
    }
}

/*
 * Free a linked list of lines.
 */
static void free_llist(Line * list)
{
    Line *l;
    while (list) {
        l = list;
        list = list->next;
        free_tlist(l->first);
        nasm_free(l);
    }
}

/*
 * Free an MMacro
 */
static void free_mmacro(MMacro * m)
{
    nasm_free(m->name);
    free_tlist(m->dlist);
    nasm_free(m->defaults);
    free_llist(m->expansion);
    nasm_free(m);
}

/*
 * Free all currently defined macros, and free the hash tables
 */
static void free_macros(void)
{
    struct hash_tbl_node *it;
    const char *key;
    SMacro *s;
    MMacro *m;

    it = NULL;
    while ((s = hash_iterate(smacros, &it, &key)) != NULL) {
	nasm_free((void *)key);
	while (s) {
	    SMacro *ns = s->next;
	    nasm_free(s->name);
	    free_tlist(s->expansion);
	    nasm_free(s);
	    s = ns;
	}
    }
    hash_free(smacros);

    it = NULL;
    while ((m = hash_iterate(mmacros, &it, &key)) != NULL) {
	nasm_free((void *)key);
	while (m) {
	    MMacro *nm = m->next;
	    free_mmacro(m);
	    m = nm;
	}
    }
    hash_free(mmacros);
}

/*
 * Initialize the hash tables
 */
static void init_macros(void)
{
    smacros = hash_init();
    mmacros = hash_init();
}

/*
 * Pop the context stack.
 */
static void ctx_pop(void)
{
    Context *c = cstk;
    SMacro *smac, *s;

    cstk = cstk->next;
    smac = c->localmac;
    while (smac) {
        s = smac;
        smac = smac->next;
        nasm_free(s->name);
        free_tlist(s->expansion);
        nasm_free(s);
    }
    nasm_free(c->name);
    nasm_free(c);
}

#define BUF_DELTA 512
/*
 * Read a line from the top file in istk, handling multiple CR/LFs
 * at the end of the line read, and handling spurious ^Zs. Will
 * return lines from the standard macro set if this has not already
 * been done.
 */
static char *read_line(void)
{
    char *buffer, *p, *q;
    int bufsize, continued_count;

    if (stdmacpos) {
        if (*stdmacpos) {
            char *ret = nasm_strdup(*stdmacpos++);
            if (!*stdmacpos && any_extrastdmac) {
                stdmacpos = extrastdmac;
                any_extrastdmac = false;
                return ret;
            }
            /*
             * Nasty hack: here we push the contents of `predef' on
             * to the top-level expansion stack, since this is the
             * most convenient way to implement the pre-include and
             * pre-define features.
             */
            if (!*stdmacpos) {
                Line *pd, *l;
                Token *head, **tail, *t;

                for (pd = predef; pd; pd = pd->next) {
                    head = NULL;
                    tail = &head;
                    for (t = pd->first; t; t = t->next) {
                        *tail = new_Token(NULL, t->type, t->text, 0);
                        tail = &(*tail)->next;
                    }
                    l = nasm_malloc(sizeof(Line));
                    l->next = istk->expansion;
                    l->first = head;
                    l->finishes = false;
                    istk->expansion = l;
                }
            }
            return ret;
        } else {
            stdmacpos = NULL;
        }
    }

    bufsize = BUF_DELTA;
    buffer = nasm_malloc(BUF_DELTA);
    p = buffer;
    continued_count = 0;
    while (1) {
        q = fgets(p, bufsize - (p - buffer), istk->fp);
        if (!q)
            break;
        p += strlen(p);
        if (p > buffer && p[-1] == '\n') {
            /* Convert backslash-CRLF line continuation sequences into
               nothing at all (for DOS and Windows) */
            if (((p - 2) > buffer) && (p[-3] == '\\') && (p[-2] == '\r')) {
                p -= 3;
                *p = 0;
                continued_count++;
            }
            /* Also convert backslash-LF line continuation sequences into
               nothing at all (for Unix) */
            else if (((p - 1) > buffer) && (p[-2] == '\\')) {
                p -= 2;
                *p = 0;
                continued_count++;
            } else {
                break;
            }
        }
        if (p - buffer > bufsize - 10) {
            int32_t offset = p - buffer;
            bufsize += BUF_DELTA;
            buffer = nasm_realloc(buffer, bufsize);
            p = buffer + offset;        /* prevent stale-pointer problems */
        }
    }

    if (!q && p == buffer) {
        nasm_free(buffer);
        return NULL;
    }

    src_set_linnum(src_get_linnum() + istk->lineinc +
                   (continued_count * istk->lineinc));

    /*
     * Play safe: remove CRs as well as LFs, if any of either are
     * present at the end of the line.
     */
    while (--p >= buffer && (*p == '\n' || *p == '\r'))
        *p = '\0';

    /*
     * Handle spurious ^Z, which may be inserted into source files
     * by some file transfer utilities.
     */
    buffer[strcspn(buffer, "\032")] = '\0';

    list->line(LIST_READ, buffer);

    return buffer;
}

/*
 * Tokenize a line of text. This is a very simple process since we
 * don't need to parse the value out of e.g. numeric tokens: we
 * simply split one string into many.
 */
static Token *tokenize(char *line)
{
    char *p = line;
    enum pp_token_type type;
    Token *list = NULL;
    Token *t, **tail = &list;

    while (*line) {
        p = line;
        if (*p == '%') {
            p++;
            if (isdigit(*p) ||
                ((*p == '-' || *p == '+') && isdigit(p[1])) ||
                ((*p == '+') && (isspace(p[1]) || !p[1]))) {
                do {
                    p++;
                }
                while (isdigit(*p));
                type = TOK_PREPROC_ID;
            } else if (*p == '{') {
                p++;
                while (*p && *p != '}') {
                    p[-1] = *p;
                    p++;
                }
                p[-1] = '\0';
                if (*p)
                    p++;
                type = TOK_PREPROC_ID;
            } else if (isidchar(*p) ||
                       ((*p == '!' || *p == '%' || *p == '$') &&
                        isidchar(p[1]))) {
                do {
                    p++;
                }
                while (isidchar(*p));
                type = TOK_PREPROC_ID;
            } else {
                type = TOK_OTHER;
                if (*p == '%')
                    p++;
            }
        } else if (isidstart(*p) || (*p == '$' && isidstart(p[1]))) {
            type = TOK_ID;
            p++;
            while (*p && isidchar(*p))
                p++;
        } else if (*p == '\'' || *p == '"') {
            /*
             * A string token.
             */
            char c = *p;
            p++;
            type = TOK_STRING;
            while (*p && *p != c)
                p++;

            if (*p) {
                p++;
            } else {
                error(ERR_WARNING, "unterminated string");
                /* Handling unterminated strings by UNV */
                /* type = -1; */
            }
        } else if (isnumstart(*p)) {
            /*
             * A number token.
             */
            type = TOK_NUMBER;
            p++;
            while (*p && isnumchar(*p))
                p++;
        } else if (isspace(*p)) {
            type = TOK_WHITESPACE;
            p++;
            while (*p && isspace(*p))
                p++;
            /*
             * Whitespace just before end-of-line is discarded by
             * pretending it's a comment; whitespace just before a
             * comment gets lumped into the comment.
             */
            if (!*p || *p == ';') {
                type = TOK_COMMENT;
                while (*p)
                    p++;
            }
        } else if (*p == ';') {
            type = TOK_COMMENT;
            while (*p)
                p++;
        } else {
            /*
             * Anything else is an operator of some kind. We check
             * for all the double-character operators (>>, <<, //,
             * %%, <=, >=, ==, !=, <>, &&, ||, ^^), but anything
             * else is a single-character operator.
             */
            type = TOK_OTHER;
            if ((p[0] == '>' && p[1] == '>') ||
                (p[0] == '<' && p[1] == '<') ||
                (p[0] == '/' && p[1] == '/') ||
                (p[0] == '<' && p[1] == '=') ||
                (p[0] == '>' && p[1] == '=') ||
                (p[0] == '=' && p[1] == '=') ||
                (p[0] == '!' && p[1] == '=') ||
                (p[0] == '<' && p[1] == '>') ||
                (p[0] == '&' && p[1] == '&') ||
                (p[0] == '|' && p[1] == '|') ||
                (p[0] == '^' && p[1] == '^')) {
                p++;
            }
            p++;
        }

        /* Handling unterminated string by UNV */
        /*if (type == -1)
           {
           *tail = t = new_Token(NULL, TOK_STRING, line, p-line+1);
           t->text[p-line] = *line;
           tail = &t->next;
           }
           else */
        if (type != TOK_COMMENT) {
            *tail = t = new_Token(NULL, type, line, p - line);
            tail = &t->next;
        }
        line = p;
    }
    return list;
}

/*
 * this function allocates a new managed block of memory and
 * returns a pointer to the block.  The managed blocks are 
 * deleted only all at once by the delete_Blocks function.
 */
static void *new_Block(size_t size)
{
    Blocks *b = &blocks;

    /* first, get to the end of the linked list */
    while (b->next)
        b = b->next;
    /* now allocate the requested chunk */
    b->chunk = nasm_malloc(size);

    /* now allocate a new block for the next request */
    b->next = nasm_malloc(sizeof(Blocks));
    /* and initialize the contents of the new block */
    b->next->next = NULL;
    b->next->chunk = NULL;
    return b->chunk;
}

/*
 * this function deletes all managed blocks of memory
 */
static void delete_Blocks(void)
{
    Blocks *a, *b = &blocks;

    /* 
     * keep in mind that the first block, pointed to by blocks
     * is a static and not dynamically allocated, so we don't 
     * free it.
     */
    while (b) {
        if (b->chunk)
            nasm_free(b->chunk);
        a = b;
        b = b->next;
        if (a != &blocks)
            nasm_free(a);
    }
}

/*
 *  this function creates a new Token and passes a pointer to it 
 *  back to the caller.  It sets the type and text elements, and
 *  also the mac and next elements to NULL.
 */
static Token *new_Token(Token * next, enum pp_token_type type, char *text, int txtlen)
{
    Token *t;
    int i;

    if (freeTokens == NULL) {
        freeTokens = (Token *) new_Block(TOKEN_BLOCKSIZE * sizeof(Token));
        for (i = 0; i < TOKEN_BLOCKSIZE - 1; i++)
            freeTokens[i].next = &freeTokens[i + 1];
        freeTokens[i].next = NULL;
    }
    t = freeTokens;
    freeTokens = t->next;
    t->next = next;
    t->mac = NULL;
    t->type = type;
    if (type == TOK_WHITESPACE || text == NULL) {
        t->text = NULL;
    } else {
        if (txtlen == 0)
            txtlen = strlen(text);
        t->text = nasm_malloc(1 + txtlen);
        strncpy(t->text, text, txtlen);
        t->text[txtlen] = '\0';
    }
    return t;
}

static Token *delete_Token(Token * t)
{
    Token *next = t->next;
    nasm_free(t->text);
    t->next = freeTokens;
    freeTokens = t;
    return next;
}

/*
 * Convert a line of tokens back into text.
 * If expand_locals is not zero, identifiers of the form "%$*xxx"
 * will be transformed into ..@ctxnum.xxx
 */
static char *detoken(Token * tlist, int expand_locals)
{
    Token *t;
    int len;
    char *line, *p;

    len = 0;
    for (t = tlist; t; t = t->next) {
        if (t->type == TOK_PREPROC_ID && t->text[1] == '!') {
            char *p = getenv(t->text + 2);
            nasm_free(t->text);
            if (p)
                t->text = nasm_strdup(p);
            else
                t->text = NULL;
        }
        /* Expand local macros here and not during preprocessing */
        if (expand_locals &&
            t->type == TOK_PREPROC_ID && t->text &&
            t->text[0] == '%' && t->text[1] == '$') {
            Context *ctx = get_ctx(t->text, false);
            if (ctx) {
                char buffer[40];
                char *p, *q = t->text + 2;

                q += strspn(q, "$");
                snprintf(buffer, sizeof(buffer), "..@%"PRIu32".", ctx->number);
                p = nasm_strcat(buffer, q);
                nasm_free(t->text);
                t->text = p;
            }
        }
        if (t->type == TOK_WHITESPACE) {
            len++;
        } else if (t->text) {
            len += strlen(t->text);
        }
    }
    p = line = nasm_malloc(len + 1);
    for (t = tlist; t; t = t->next) {
        if (t->type == TOK_WHITESPACE) {
            *p = ' ';
            p++;
            *p = '\0';
        } else if (t->text) {
            strcpy(p, t->text);
            p += strlen(p);
        }
    }
    *p = '\0';
    return line;
}

/*
 * A scanner, suitable for use by the expression evaluator, which
 * operates on a line of Tokens. Expects a pointer to a pointer to
 * the first token in the line to be passed in as its private_data
 * field.
 */
static int ppscan(void *private_data, struct tokenval *tokval)
{
    Token **tlineptr = private_data;
    Token *tline;

    do {
        tline = *tlineptr;
        *tlineptr = tline ? tline->next : NULL;
    }
    while (tline && (tline->type == TOK_WHITESPACE ||
                     tline->type == TOK_COMMENT));

    if (!tline)
        return tokval->t_type = TOKEN_EOS;

    if (tline->text[0] == '$' && !tline->text[1])
        return tokval->t_type = TOKEN_HERE;
    if (tline->text[0] == '$' && tline->text[1] == '$' && !tline->text[2])
        return tokval->t_type = TOKEN_BASE;

    if (tline->type == TOK_ID) {
        tokval->t_charptr = tline->text;
        if (tline->text[0] == '$') {
            tokval->t_charptr++;
            return tokval->t_type = TOKEN_ID;
        }

        /*
         * This is the only special case we actually need to worry
         * about in this restricted context.
         */
        if (!nasm_stricmp(tline->text, "seg"))
            return tokval->t_type = TOKEN_SEG;

        return tokval->t_type = TOKEN_ID;
    }

    if (tline->type == TOK_NUMBER) {
        bool rn_error;

        tokval->t_integer = readnum(tline->text, &rn_error);
        if (rn_error)
            return tokval->t_type = TOKEN_ERRNUM;
        tokval->t_charptr = NULL;
        return tokval->t_type = TOKEN_NUM;
    }

    if (tline->type == TOK_STRING) {
        int rn_warn;
        char q, *r;
        int l;

        r = tline->text;
        q = *r++;
        l = strlen(r);

        if (l == 0 || r[l - 1] != q)
            return tokval->t_type = TOKEN_ERRNUM;
        tokval->t_integer = readstrnum(r, l - 1, &rn_warn);
        if (rn_warn)
            error(ERR_WARNING | ERR_PASS1, "character constant too long");
        tokval->t_charptr = NULL;
        return tokval->t_type = TOKEN_NUM;
    }

    if (tline->type == TOK_OTHER) {
        if (!strcmp(tline->text, "<<"))
            return tokval->t_type = TOKEN_SHL;
        if (!strcmp(tline->text, ">>"))
            return tokval->t_type = TOKEN_SHR;
        if (!strcmp(tline->text, "//"))
            return tokval->t_type = TOKEN_SDIV;
        if (!strcmp(tline->text, "%%"))
            return tokval->t_type = TOKEN_SMOD;
        if (!strcmp(tline->text, "=="))
            return tokval->t_type = TOKEN_EQ;
        if (!strcmp(tline->text, "<>"))
            return tokval->t_type = TOKEN_NE;
        if (!strcmp(tline->text, "!="))
            return tokval->t_type = TOKEN_NE;
        if (!strcmp(tline->text, "<="))
            return tokval->t_type = TOKEN_LE;
        if (!strcmp(tline->text, ">="))
            return tokval->t_type = TOKEN_GE;
        if (!strcmp(tline->text, "&&"))
            return tokval->t_type = TOKEN_DBL_AND;
        if (!strcmp(tline->text, "^^"))
            return tokval->t_type = TOKEN_DBL_XOR;
        if (!strcmp(tline->text, "||"))
            return tokval->t_type = TOKEN_DBL_OR;
    }

    /*
     * We have no other options: just return the first character of
     * the token text.
     */
    return tokval->t_type = tline->text[0];
}

/*
 * Compare a string to the name of an existing macro; this is a
 * simple wrapper which calls either strcmp or nasm_stricmp
 * depending on the value of the `casesense' parameter.
 */
static int mstrcmp(char *p, char *q, bool casesense)
{
    return casesense ? strcmp(p, q) : nasm_stricmp(p, q);
}

/*
 * Return the Context structure associated with a %$ token. Return
 * NULL, having _already_ reported an error condition, if the
 * context stack isn't deep enough for the supplied number of $
 * signs.
 * If all_contexts == true, contexts that enclose current are
 * also scanned for such smacro, until it is found; if not -
 * only the context that directly results from the number of $'s
 * in variable's name.
 */
static Context *get_ctx(char *name, bool all_contexts)
{
    Context *ctx;
    SMacro *m;
    int i;

    if (!name || name[0] != '%' || name[1] != '$')
        return NULL;

    if (!cstk) {
        error(ERR_NONFATAL, "`%s': context stack is empty", name);
        return NULL;
    }

    for (i = strspn(name + 2, "$"), ctx = cstk; (i > 0) && ctx; i--) {
        ctx = ctx->next;
/*        i--;  Lino - 02/25/02 */
    }
    if (!ctx) {
        error(ERR_NONFATAL, "`%s': context stack is only"
              " %d level%s deep", name, i - 1, (i == 2 ? "" : "s"));
        return NULL;
    }
    if (!all_contexts)
        return ctx;

    do {
        /* Search for this smacro in found context */
        m = ctx->localmac;
        while (m) {
            if (!mstrcmp(m->name, name, m->casesense))
                return ctx;
            m = m->next;
        }
        ctx = ctx->next;
    }
    while (ctx);
    return NULL;
}

/*
 * Open an include file. This routine must always return a valid
 * file pointer if it returns - it's responsible for throwing an
 * ERR_FATAL and bombing out completely if not. It should also try
 * the include path one by one until it finds the file or reaches
 * the end of the path.
 */
static FILE *inc_fopen(char *file)
{
    FILE *fp;
    char *prefix = "", *combine;
    IncPath *ip = ipath;
    static int namelen = 0;
    int len = strlen(file);

    while (1) {
        combine = nasm_malloc(strlen(prefix) + len + 1);
        strcpy(combine, prefix);
        strcat(combine, file);
        fp = fopen(combine, "r");
        if (pass == 0 && fp) {
            namelen += strlen(combine) + 1;
            if (namelen > 62) {
                printf(" \\\n  ");
                namelen = 2;
            }
            printf(" %s", combine);
        }
        nasm_free(combine);
        if (fp)
            return fp;
        if (!ip)
            break;
        prefix = ip->path;
        ip = ip->next;

	if (!prefix) {
		/* -MG given and file not found */
		if (pass == 0) {
			namelen += strlen(file) + 1;
			if (namelen > 62) {
				printf(" \\\n  ");
				namelen = 2;
			}
			printf(" %s", file);
		}
	    return NULL;
	}
    }

    error(ERR_FATAL, "unable to open include file `%s'", file);
    return NULL;                /* never reached - placate compilers */
}

/*
 * Search for a key in the hash index; adding it if necessary
 * (in which case we initialize the data pointer to NULL.)
 */
static void **
hash_findi_add(struct hash_table *hash, const char *str)
{
    struct hash_insert hi;
    void **r;
    char *strx;

    r = hash_findi(hash, str, &hi);
    if (r)
	return r;

    strx = nasm_strdup(str);	/* Use a more efficient allocator here? */
    return hash_add(&hi, strx, NULL);
}

/*
 * Like hash_findi, but returns the data element rather than a pointer
 * to it.  Used only when not adding a new element, hence no third
 * argument.
 */
static void *
hash_findix(struct hash_table *hash, const char *str)
{
    void **p;

    p = hash_findi(hash, str, NULL);
    return p ? *p : NULL;
}

/*
 * Determine if we should warn on defining a single-line macro of
 * name `name', with `nparam' parameters. If nparam is 0 or -1, will
 * return true if _any_ single-line macro of that name is defined.
 * Otherwise, will return true if a single-line macro with either
 * `nparam' or no parameters is defined.
 *
 * If a macro with precisely the right number of parameters is
 * defined, or nparam is -1, the address of the definition structure
 * will be returned in `defn'; otherwise NULL will be returned. If `defn'
 * is NULL, no action will be taken regarding its contents, and no
 * error will occur.
 *
 * Note that this is also called with nparam zero to resolve
 * `ifdef'.
 *
 * If you already know which context macro belongs to, you can pass
 * the context pointer as first parameter; if you won't but name begins
 * with %$ the context will be automatically computed. If all_contexts
 * is true, macro will be searched in outer contexts as well.
 */
static int
smacro_defined(Context * ctx, char *name, int nparam, SMacro ** defn,
               int nocase)
{
    SMacro *m;

    if (ctx) {
        m = ctx->localmac;
    } else if (name[0] == '%' && name[1] == '$') {
	if (cstk)
            ctx = get_ctx(name, false);
        if (!ctx)
            return false;       /* got to return _something_ */
        m = ctx->localmac;
    } else {
	m = (SMacro *) hash_findix(smacros, name);
    }

    while (m) {
        if (!mstrcmp(m->name, name, m->casesense && nocase) &&
            (nparam <= 0 || m->nparam == 0 || nparam == m->nparam)) {
            if (defn) {
                if (nparam == m->nparam || nparam == -1)
                    *defn = m;
                else
                    *defn = NULL;
            }
            return true;
        }
        m = m->next;
    }

    return false;
}

/*
 * Count and mark off the parameters in a multi-line macro call.
 * This is called both from within the multi-line macro expansion
 * code, and also to mark off the default parameters when provided
 * in a %macro definition line.
 */
static void count_mmac_params(Token * t, int *nparam, Token *** params)
{
    int paramsize, brace;

    *nparam = paramsize = 0;
    *params = NULL;
    while (t) {
        if (*nparam >= paramsize) {
            paramsize += PARAM_DELTA;
            *params = nasm_realloc(*params, sizeof(**params) * paramsize);
        }
        skip_white_(t);
        brace = false;
        if (tok_is_(t, "{"))
            brace = true;
        (*params)[(*nparam)++] = t;
        while (tok_isnt_(t, brace ? "}" : ","))
            t = t->next;
        if (t) {                /* got a comma/brace */
            t = t->next;
            if (brace) {
                /*
                 * Now we've found the closing brace, look further
                 * for the comma.
                 */
                skip_white_(t);
                if (tok_isnt_(t, ",")) {
                    error(ERR_NONFATAL,
                          "braces do not enclose all of macro parameter");
                    while (tok_isnt_(t, ","))
                        t = t->next;
                }
                if (t)
                    t = t->next;        /* eat the comma */
            }
        }
    }
}

/*
 * Determine whether one of the various `if' conditions is true or
 * not.
 *
 * We must free the tline we get passed.
 */
static bool if_condition(Token * tline, enum preproc_token ct)
{
    enum pp_conditional i = PP_COND(ct);
    bool j;
    Token *t, *tt, **tptr, *origline;
    struct tokenval tokval;
    expr *evalresult;
    enum pp_token_type needtype;

    origline = tline;

    switch (i) {
    case PPC_IFCTX:
        j = false;              /* have we matched yet? */
        while (cstk && tline) {
            skip_white_(tline);
            if (!tline || tline->type != TOK_ID) {
                error(ERR_NONFATAL,
                      "`%s' expects context identifiers", pp_directives[ct]);
                free_tlist(origline);
                return -1;
            }
            if (!nasm_stricmp(tline->text, cstk->name))
                j = true;
            tline = tline->next;
        }
	break;

    case PPC_IFDEF:
        j = false;              /* have we matched yet? */
        while (tline) {
            skip_white_(tline);
            if (!tline || (tline->type != TOK_ID &&
                           (tline->type != TOK_PREPROC_ID ||
                            tline->text[1] != '$'))) {
                error(ERR_NONFATAL,
                      "`%s' expects macro identifiers", pp_directives[ct]);
		goto fail;
            }
            if (smacro_defined(NULL, tline->text, 0, NULL, 1))
                j = true;
            tline = tline->next;
        }
	break;

    case PPC_IFIDN:
    case PPC_IFIDNI:
        tline = expand_smacro(tline);
        t = tt = tline;
        while (tok_isnt_(tt, ","))
            tt = tt->next;
        if (!tt) {
            error(ERR_NONFATAL,
                  "`%s' expects two comma-separated arguments",
                  pp_directives[ct]);
	    goto fail;
        }
        tt = tt->next;
        j = true;               /* assume equality unless proved not */
        while ((t->type != TOK_OTHER || strcmp(t->text, ",")) && tt) {
            if (tt->type == TOK_OTHER && !strcmp(tt->text, ",")) {
                error(ERR_NONFATAL, "`%s': more than one comma on line",
                      pp_directives[ct]);
		goto fail;
            }
            if (t->type == TOK_WHITESPACE) {
                t = t->next;
                continue;
            }
            if (tt->type == TOK_WHITESPACE) {
                tt = tt->next;
                continue;
            }
            if (tt->type != t->type) {
                j = false;      /* found mismatching tokens */
                break;
            }
            /* Unify surrounding quotes for strings */
            if (t->type == TOK_STRING) {
                tt->text[0] = t->text[0];
                tt->text[strlen(tt->text) - 1] = t->text[0];
            }
            if (mstrcmp(tt->text, t->text, i == PPC_IFIDN) != 0) {
                j = false;      /* found mismatching tokens */
                break;
            }

            t = t->next;
            tt = tt->next;
        }
        if ((t->type != TOK_OTHER || strcmp(t->text, ",")) || tt)
            j = false;          /* trailing gunk on one end or other */
	break;

    case PPC_IFMACRO:
        {
            bool found = false;
            MMacro searching, *mmac;

            tline = tline->next;
            skip_white_(tline);
            tline = expand_id(tline);
            if (!tok_type_(tline, TOK_ID)) {
                error(ERR_NONFATAL,
                      "`%s' expects a macro name", pp_directives[ct]);
		goto fail;
            }
            searching.name = nasm_strdup(tline->text);
            searching.casesense = (i == PP_MACRO);
            searching.plus = false;
            searching.nolist = false;
            searching.in_progress = false;
            searching.rep_nest = NULL;
            searching.nparam_min = 0;
            searching.nparam_max = INT_MAX;
            tline = expand_smacro(tline->next);
            skip_white_(tline);
            if (!tline) {
            } else if (!tok_type_(tline, TOK_NUMBER)) {
                error(ERR_NONFATAL,
                      "`%s' expects a parameter count or nothing",
                      pp_directives[ct]);
            } else {
                searching.nparam_min = searching.nparam_max =
                    readnum(tline->text, &j);
                if (j)
                    error(ERR_NONFATAL,
                          "unable to parse parameter count `%s'",
                          tline->text);
            }
            if (tline && tok_is_(tline->next, "-")) {
                tline = tline->next->next;
                if (tok_is_(tline, "*"))
                    searching.nparam_max = INT_MAX;
                else if (!tok_type_(tline, TOK_NUMBER))
                    error(ERR_NONFATAL,
                          "`%s' expects a parameter count after `-'",
                          pp_directives[ct]);
                else {
                    searching.nparam_max = readnum(tline->text, &j);
                    if (j)
                        error(ERR_NONFATAL,
                              "unable to parse parameter count `%s'",
                              tline->text);
                    if (searching.nparam_min > searching.nparam_max)
                        error(ERR_NONFATAL,
                              "minimum parameter count exceeds maximum");
                }
            }
            if (tline && tok_is_(tline->next, "+")) {
                tline = tline->next;
                searching.plus = true;
            }
            mmac = (MMacro *) hash_findix(mmacros, searching.name);
	    while (mmac) {
		if (!strcmp(mmac->name, searching.name) &&
		    (mmac->nparam_min <= searching.nparam_max
		     || searching.plus)
		    && (searching.nparam_min <= mmac->nparam_max
			|| mmac->plus)) {
		    found = true;
		    break;
		}
		mmac = mmac->next;
	    }
            nasm_free(searching.name);
	    j = found;
	    break;
        }

    case PPC_IFID:
	needtype = TOK_ID;
	goto iftype;
    case PPC_IFNUM:
	needtype = TOK_NUMBER;
	goto iftype;
    case PPC_IFSTR:
	needtype = TOK_STRING;
	goto iftype;

    iftype:
        tline = expand_smacro(tline);
        t = tline;
        while (tok_type_(t, TOK_WHITESPACE))
            t = t->next;
        j = false;              /* placate optimiser */
        if (t)
	    j = t->type == needtype;
	break;

    case PPC_IF:
        t = tline = expand_smacro(tline);
        tptr = &t;
        tokval.t_type = TOKEN_INVALID;
        evalresult = evaluate(ppscan, tptr, &tokval,
                              NULL, pass | CRITICAL, error, NULL);
        if (!evalresult)
            return -1;
        if (tokval.t_type)
            error(ERR_WARNING,
                  "trailing garbage after expression ignored");
        if (!is_simple(evalresult)) {
            error(ERR_NONFATAL,
                  "non-constant value given to `%s'", pp_directives[ct]);
	    goto fail;
        }
        j = reloc_value(evalresult) != 0;
        return j;

    default:
        error(ERR_FATAL,
              "preprocessor directive `%s' not yet implemented",
              pp_directives[ct]);
	goto fail;
    }

    free_tlist(origline);
    return j ^ PP_NEGATIVE(ct);
    
fail:
    free_tlist(origline);
    return -1;
}

/*
 * Expand macros in a string. Used in %error and %include directives.
 * First tokenize the string, apply "expand_smacro" and then de-tokenize back.
 * The returned variable should ALWAYS be freed after usage.
 */
void expand_macros_in_string(char **p)
{
    Token *line = tokenize(*p);
    line = expand_smacro(line);
    *p = detoken(line, false);
}

/**
 * find and process preprocessor directive in passed line
 * Find out if a line contains a preprocessor directive, and deal
 * with it if so.
 * 
 * If a directive _is_ found, it is the responsibility of this routine
 * (and not the caller) to free_tlist() the line.
 *
 * @param tline a pointer to the current tokeninzed line linked list
 * @return DIRECTIVE_FOUND or NO_DIRECTIVE_FOUND
 * 
 */
static int do_directive(Token * tline)
{
    enum preproc_token i;
    int j;
    bool err;
    int nparam;
    bool nolist;
    int k, m;
    int offset;
    char *p, *mname;
    Include *inc;
    Context *ctx;
    Cond *cond;
    SMacro *smac, **smhead;
    MMacro *mmac, **mmhead;
    Token *t, *tt, *param_start, *macro_start, *last, **tptr, *origline;
    Line *l;
    struct tokenval tokval;
    expr *evalresult;
    MMacro *tmp_defining;       /* Used when manipulating rep_nest */

    origline = tline;

    skip_white_(tline);
    if (!tok_type_(tline, TOK_PREPROC_ID) ||
        (tline->text[1] == '%' || tline->text[1] == '$'
         || tline->text[1] == '!'))
        return NO_DIRECTIVE_FOUND;

    i = pp_token_hash(tline->text);

    /*
     * If we're in a non-emitting branch of a condition construct,
     * or walking to the end of an already terminated %rep block,
     * we should ignore all directives except for condition
     * directives.
     */
    if (((istk->conds && !emitting(istk->conds->state)) ||
         (istk->mstk && !istk->mstk->in_progress)) && !is_condition(i)) {
        return NO_DIRECTIVE_FOUND;
    }

    /*
     * If we're defining a macro or reading a %rep block, we should
     * ignore all directives except for %macro/%imacro (which
     * generate an error), %endm/%endmacro, and (only if we're in a
     * %rep block) %endrep. If we're in a %rep block, another %rep
     * causes an error, so should be let through.
     */
    if (defining && i != PP_MACRO && i != PP_IMACRO &&
        i != PP_ENDMACRO && i != PP_ENDM &&
        (defining->name || (i != PP_ENDREP && i != PP_REP))) {
        return NO_DIRECTIVE_FOUND;
    }

    switch (i) {
    case PP_INVALID:
        error(ERR_NONFATAL, "unknown preprocessor directive `%s'",
              tline->text);
        return NO_DIRECTIVE_FOUND;      /* didn't get it */

    case PP_STACKSIZE:
        /* Directive to tell NASM what the default stack size is. The
         * default is for a 16-bit stack, and this can be overriden with
         * %stacksize large.
         * the following form:
         *
         *      ARG arg1:WORD, arg2:DWORD, arg4:QWORD
         */
        tline = tline->next;
        if (tline && tline->type == TOK_WHITESPACE)
            tline = tline->next;
        if (!tline || tline->type != TOK_ID) {
            error(ERR_NONFATAL, "`%%stacksize' missing size parameter");
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }
        if (nasm_stricmp(tline->text, "flat") == 0) {
            /* All subsequent ARG directives are for a 32-bit stack */
            StackSize = 4;
            StackPointer = "ebp";
            ArgOffset = 8;
            LocalOffset = 4;
        } else if (nasm_stricmp(tline->text, "large") == 0) {
            /* All subsequent ARG directives are for a 16-bit stack,
             * far function call.
             */
            StackSize = 2;
            StackPointer = "bp";
            ArgOffset = 4;
            LocalOffset = 2;
        } else if (nasm_stricmp(tline->text, "small") == 0) {
            /* All subsequent ARG directives are for a 16-bit stack,
             * far function call. We don't support near functions.
             */
            StackSize = 2;
            StackPointer = "bp";
            ArgOffset = 6;
            LocalOffset = 2;
        } else {
            error(ERR_NONFATAL, "`%%stacksize' invalid size type");
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_ARG:
        /* TASM like ARG directive to define arguments to functions, in
         * the following form:
         *
         *      ARG arg1:WORD, arg2:DWORD, arg4:QWORD
         */
        offset = ArgOffset;
        do {
            char *arg, directive[256];
            int size = StackSize;

            /* Find the argument name */
            tline = tline->next;
            if (tline && tline->type == TOK_WHITESPACE)
                tline = tline->next;
            if (!tline || tline->type != TOK_ID) {
                error(ERR_NONFATAL, "`%%arg' missing argument parameter");
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }
            arg = tline->text;

            /* Find the argument size type */
            tline = tline->next;
            if (!tline || tline->type != TOK_OTHER
                || tline->text[0] != ':') {
                error(ERR_NONFATAL,
                      "Syntax error processing `%%arg' directive");
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }
            tline = tline->next;
            if (!tline || tline->type != TOK_ID) {
                error(ERR_NONFATAL, "`%%arg' missing size type parameter");
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }

            /* Allow macro expansion of type parameter */
            tt = tokenize(tline->text);
            tt = expand_smacro(tt);
            if (nasm_stricmp(tt->text, "byte") == 0) {
                size = MAX(StackSize, 1);
            } else if (nasm_stricmp(tt->text, "word") == 0) {
                size = MAX(StackSize, 2);
            } else if (nasm_stricmp(tt->text, "dword") == 0) {
                size = MAX(StackSize, 4);
            } else if (nasm_stricmp(tt->text, "qword") == 0) {
                size = MAX(StackSize, 8);
            } else if (nasm_stricmp(tt->text, "tword") == 0) {
                size = MAX(StackSize, 10);
            } else {
                error(ERR_NONFATAL,
                      "Invalid size type for `%%arg' missing directive");
                free_tlist(tt);
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }
            free_tlist(tt);

            /* Now define the macro for the argument */
            snprintf(directive, sizeof(directive), "%%define %s (%s+%d)",
                     arg, StackPointer, offset);
            do_directive(tokenize(directive));
            offset += size;

            /* Move to the next argument in the list */
            tline = tline->next;
            if (tline && tline->type == TOK_WHITESPACE)
                tline = tline->next;
        }
        while (tline && tline->type == TOK_OTHER && tline->text[0] == ',');
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_LOCAL:
        /* TASM like LOCAL directive to define local variables for a
         * function, in the following form:
         *
         *      LOCAL local1:WORD, local2:DWORD, local4:QWORD = LocalSize
         *
         * The '= LocalSize' at the end is ignored by NASM, but is
         * required by TASM to define the local parameter size (and used
         * by the TASM macro package).
         */
        offset = LocalOffset;
        do {
            char *local, directive[256];
            int size = StackSize;

            /* Find the argument name */
            tline = tline->next;
            if (tline && tline->type == TOK_WHITESPACE)
                tline = tline->next;
            if (!tline || tline->type != TOK_ID) {
                error(ERR_NONFATAL,
                      "`%%local' missing argument parameter");
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }
            local = tline->text;

            /* Find the argument size type */
            tline = tline->next;
            if (!tline || tline->type != TOK_OTHER
                || tline->text[0] != ':') {
                error(ERR_NONFATAL,
                      "Syntax error processing `%%local' directive");
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }
            tline = tline->next;
            if (!tline || tline->type != TOK_ID) {
                error(ERR_NONFATAL,
                      "`%%local' missing size type parameter");
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }

            /* Allow macro expansion of type parameter */
            tt = tokenize(tline->text);
            tt = expand_smacro(tt);
            if (nasm_stricmp(tt->text, "byte") == 0) {
                size = MAX(StackSize, 1);
            } else if (nasm_stricmp(tt->text, "word") == 0) {
                size = MAX(StackSize, 2);
            } else if (nasm_stricmp(tt->text, "dword") == 0) {
                size = MAX(StackSize, 4);
            } else if (nasm_stricmp(tt->text, "qword") == 0) {
                size = MAX(StackSize, 8);
            } else if (nasm_stricmp(tt->text, "tword") == 0) {
                size = MAX(StackSize, 10);
            } else {
                error(ERR_NONFATAL,
                      "Invalid size type for `%%local' missing directive");
                free_tlist(tt);
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }
            free_tlist(tt);

            /* Now define the macro for the argument */
            snprintf(directive, sizeof(directive), "%%define %s (%s-%d)",
                     local, StackPointer, offset);
            do_directive(tokenize(directive));
            offset += size;

            /* Now define the assign to setup the enter_c macro correctly */
            snprintf(directive, sizeof(directive),
                     "%%assign %%$localsize %%$localsize+%d", size);
            do_directive(tokenize(directive));

            /* Move to the next argument in the list */
            tline = tline->next;
            if (tline && tline->type == TOK_WHITESPACE)
                tline = tline->next;
        }
        while (tline && tline->type == TOK_OTHER && tline->text[0] == ',');
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_CLEAR:
        if (tline->next)
            error(ERR_WARNING, "trailing garbage after `%%clear' ignored");
	free_macros();
	init_macros();
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_INCLUDE:
        tline = tline->next;
        skip_white_(tline);
        if (!tline || (tline->type != TOK_STRING &&
                       tline->type != TOK_INTERNAL_STRING)) {
            error(ERR_NONFATAL, "`%%include' expects a file name");
            free_tlist(origline);
            return DIRECTIVE_FOUND;     /* but we did _something_ */
        }
        if (tline->next)
            error(ERR_WARNING,
                  "trailing garbage after `%%include' ignored");
        if (tline->type != TOK_INTERNAL_STRING) {
            p = tline->text + 1;        /* point past the quote to the name */
            p[strlen(p) - 1] = '\0';    /* remove the trailing quote */
        } else
            p = tline->text;    /* internal_string is easier */
        expand_macros_in_string(&p);
        inc = nasm_malloc(sizeof(Include));
        inc->next = istk;
        inc->conds = NULL;
        inc->fp = inc_fopen(p);
	if (!inc->fp && pass == 0) {
	    /* -MG given but file not found */
	    nasm_free(inc);
	} else {
	    inc->fname = src_set_fname(p);
	    inc->lineno = src_set_linnum(0);
	    inc->lineinc = 1;
	    inc->expansion = NULL;
	    inc->mstk = NULL;
	    istk = inc;
	    list->uplevel(LIST_INCLUDE);
	}
	free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_PUSH:
        tline = tline->next;
        skip_white_(tline);
        tline = expand_id(tline);
        if (!tok_type_(tline, TOK_ID)) {
            error(ERR_NONFATAL, "`%%push' expects a context identifier");
            free_tlist(origline);
            return DIRECTIVE_FOUND;     /* but we did _something_ */
        }
        if (tline->next)
            error(ERR_WARNING, "trailing garbage after `%%push' ignored");
        ctx = nasm_malloc(sizeof(Context));
        ctx->next = cstk;
        ctx->localmac = NULL;
        ctx->name = nasm_strdup(tline->text);
        ctx->number = unique++;
        cstk = ctx;
        free_tlist(origline);
        break;

    case PP_REPL:
        tline = tline->next;
        skip_white_(tline);
        tline = expand_id(tline);
        if (!tok_type_(tline, TOK_ID)) {
            error(ERR_NONFATAL, "`%%repl' expects a context identifier");
            free_tlist(origline);
            return DIRECTIVE_FOUND;     /* but we did _something_ */
        }
        if (tline->next)
            error(ERR_WARNING, "trailing garbage after `%%repl' ignored");
        if (!cstk)
            error(ERR_NONFATAL, "`%%repl': context stack is empty");
        else {
            nasm_free(cstk->name);
            cstk->name = nasm_strdup(tline->text);
        }
        free_tlist(origline);
        break;

    case PP_POP:
        if (tline->next)
            error(ERR_WARNING, "trailing garbage after `%%pop' ignored");
        if (!cstk)
            error(ERR_NONFATAL, "`%%pop': context stack is already empty");
        else
            ctx_pop();
        free_tlist(origline);
        break;

    case PP_ERROR:
        tline->next = expand_smacro(tline->next);
        tline = tline->next;
        skip_white_(tline);
        if (tok_type_(tline, TOK_STRING)) {
            p = tline->text + 1;        /* point past the quote to the name */
            p[strlen(p) - 1] = '\0';    /* remove the trailing quote */
            expand_macros_in_string(&p);
            error(ERR_NONFATAL, "%s", p);
            nasm_free(p);
        } else {
            p = detoken(tline, false);
            error(ERR_WARNING, "%s", p);
            nasm_free(p);
        }
        free_tlist(origline);
        break;

    CASE_PP_IF:
        if (istk->conds && !emitting(istk->conds->state))
            j = COND_NEVER;
        else {
            j = if_condition(tline->next, i);
            tline->next = NULL; /* it got freed */
            free_tlist(origline);
            j = j < 0 ? COND_NEVER : j ? COND_IF_TRUE : COND_IF_FALSE;
        }
        cond = nasm_malloc(sizeof(Cond));
        cond->next = istk->conds;
        cond->state = j;
        istk->conds = cond;
        return DIRECTIVE_FOUND;

    CASE_PP_ELIF:
        if (!istk->conds)
            error(ERR_FATAL, "`%s': no matching `%%if'", pp_directives[i]);
        if (emitting(istk->conds->state)
            || istk->conds->state == COND_NEVER)
            istk->conds->state = COND_NEVER;
        else {
            /*
             * IMPORTANT: In the case of %if, we will already have
             * called expand_mmac_params(); however, if we're
             * processing an %elif we must have been in a
             * non-emitting mode, which would have inhibited
             * the normal invocation of expand_mmac_params().  Therefore,
             * we have to do it explicitly here.
             */
            j = if_condition(expand_mmac_params(tline->next), i);
            tline->next = NULL; /* it got freed */
            free_tlist(origline);
            istk->conds->state =
                j < 0 ? COND_NEVER : j ? COND_IF_TRUE : COND_IF_FALSE;
        }
        return DIRECTIVE_FOUND;

    case PP_ELSE:
        if (tline->next)
            error(ERR_WARNING, "trailing garbage after `%%else' ignored");
        if (!istk->conds)
            error(ERR_FATAL, "`%%else': no matching `%%if'");
        if (emitting(istk->conds->state)
            || istk->conds->state == COND_NEVER)
            istk->conds->state = COND_ELSE_FALSE;
        else
            istk->conds->state = COND_ELSE_TRUE;
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_ENDIF:
        if (tline->next)
            error(ERR_WARNING, "trailing garbage after `%%endif' ignored");
        if (!istk->conds)
            error(ERR_FATAL, "`%%endif': no matching `%%if'");
        cond = istk->conds;
        istk->conds = cond->next;
        nasm_free(cond);
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_MACRO:
    case PP_IMACRO:
        if (defining)
            error(ERR_FATAL,
                  "`%%%smacro': already defining a macro",
                  (i == PP_IMACRO ? "i" : ""));
        tline = tline->next;
        skip_white_(tline);
        tline = expand_id(tline);
        if (!tok_type_(tline, TOK_ID)) {
            error(ERR_NONFATAL,
                  "`%%%smacro' expects a macro name",
                  (i == PP_IMACRO ? "i" : ""));
            return DIRECTIVE_FOUND;
        }
        defining = nasm_malloc(sizeof(MMacro));
        defining->name = nasm_strdup(tline->text);
        defining->casesense = (i == PP_MACRO);
        defining->plus = false;
        defining->nolist = false;
        defining->in_progress = false;
        defining->rep_nest = NULL;
        tline = expand_smacro(tline->next);
        skip_white_(tline);
        if (!tok_type_(tline, TOK_NUMBER)) {
            error(ERR_NONFATAL,
                  "`%%%smacro' expects a parameter count",
                  (i == PP_IMACRO ? "i" : ""));
            defining->nparam_min = defining->nparam_max = 0;
        } else {
            defining->nparam_min = defining->nparam_max =
                readnum(tline->text, &err);
            if (err)
                error(ERR_NONFATAL,
                      "unable to parse parameter count `%s'", tline->text);
        }
        if (tline && tok_is_(tline->next, "-")) {
            tline = tline->next->next;
            if (tok_is_(tline, "*"))
                defining->nparam_max = INT_MAX;
            else if (!tok_type_(tline, TOK_NUMBER))
                error(ERR_NONFATAL,
                      "`%%%smacro' expects a parameter count after `-'",
                      (i == PP_IMACRO ? "i" : ""));
            else {
                defining->nparam_max = readnum(tline->text, &err);
                if (err)
                    error(ERR_NONFATAL,
                          "unable to parse parameter count `%s'",
                          tline->text);
                if (defining->nparam_min > defining->nparam_max)
                    error(ERR_NONFATAL,
                          "minimum parameter count exceeds maximum");
            }
        }
        if (tline && tok_is_(tline->next, "+")) {
            tline = tline->next;
            defining->plus = true;
        }
        if (tline && tok_type_(tline->next, TOK_ID) &&
            !nasm_stricmp(tline->next->text, ".nolist")) {
            tline = tline->next;
            defining->nolist = true;
        }
        mmac = (MMacro *) hash_findix(mmacros, defining->name);
        while (mmac) {
            if (!strcmp(mmac->name, defining->name) &&
                (mmac->nparam_min <= defining->nparam_max
                 || defining->plus)
                && (defining->nparam_min <= mmac->nparam_max
                    || mmac->plus)) {
                error(ERR_WARNING,
                      "redefining multi-line macro `%s'", defining->name);
                break;
            }
            mmac = mmac->next;
        }
        /*
         * Handle default parameters.
         */
        if (tline && tline->next) {
            defining->dlist = tline->next;
            tline->next = NULL;
            count_mmac_params(defining->dlist, &defining->ndefs,
                              &defining->defaults);
        } else {
            defining->dlist = NULL;
            defining->defaults = NULL;
        }
        defining->expansion = NULL;
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_ENDM:
    case PP_ENDMACRO:
        if (!defining) {
            error(ERR_NONFATAL, "`%s': not defining a macro", tline->text);
            return DIRECTIVE_FOUND;
        }
	mmhead = (MMacro **) hash_findi_add(mmacros, defining->name);
        defining->next = *mmhead;
	*mmhead = defining;
        defining = NULL;
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_ROTATE:
        if (tline->next && tline->next->type == TOK_WHITESPACE)
            tline = tline->next;
        if (tline->next == NULL) {
            free_tlist(origline);
            error(ERR_NONFATAL, "`%%rotate' missing rotate count");
            return DIRECTIVE_FOUND;
        }
        t = expand_smacro(tline->next);
        tline->next = NULL;
        free_tlist(origline);
        tline = t;
        tptr = &t;
        tokval.t_type = TOKEN_INVALID;
        evalresult =
            evaluate(ppscan, tptr, &tokval, NULL, pass, error, NULL);
        free_tlist(tline);
        if (!evalresult)
            return DIRECTIVE_FOUND;
        if (tokval.t_type)
            error(ERR_WARNING,
                  "trailing garbage after expression ignored");
        if (!is_simple(evalresult)) {
            error(ERR_NONFATAL, "non-constant value given to `%%rotate'");
            return DIRECTIVE_FOUND;
        }
        mmac = istk->mstk;
        while (mmac && !mmac->name)     /* avoid mistaking %reps for macros */
            mmac = mmac->next_active;
        if (!mmac) {
            error(ERR_NONFATAL, "`%%rotate' invoked outside a macro call");
        } else if (mmac->nparam == 0) {
            error(ERR_NONFATAL,
                  "`%%rotate' invoked within macro without parameters");
        } else {
	    int rotate = mmac->rotate + reloc_value(evalresult);

	    rotate %= (int)mmac->nparam;
	    if (rotate < 0)
		rotate += mmac->nparam;
	    
	    mmac->rotate = rotate;
        }
        return DIRECTIVE_FOUND;

    case PP_REP:
        nolist = false;
        do {
            tline = tline->next;
        } while (tok_type_(tline, TOK_WHITESPACE));

        if (tok_type_(tline, TOK_ID) &&
            nasm_stricmp(tline->text, ".nolist") == 0) {
            nolist = true;
            do {
                tline = tline->next;
            } while (tok_type_(tline, TOK_WHITESPACE));
        }

        if (tline) {
            t = expand_smacro(tline);
            tptr = &t;
            tokval.t_type = TOKEN_INVALID;
            evalresult =
                evaluate(ppscan, tptr, &tokval, NULL, pass, error, NULL);
            if (!evalresult) {
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }
            if (tokval.t_type)
                error(ERR_WARNING,
                      "trailing garbage after expression ignored");
            if (!is_simple(evalresult)) {
                error(ERR_NONFATAL, "non-constant value given to `%%rep'");
                return DIRECTIVE_FOUND;
            }
            i = (int)reloc_value(evalresult) + 1;
        } else {
            error(ERR_NONFATAL, "`%%rep' expects a repeat count");
            i = 0;
        }
        free_tlist(origline);

        tmp_defining = defining;
        defining = nasm_malloc(sizeof(MMacro));
        defining->name = NULL;  /* flags this macro as a %rep block */
        defining->casesense = false;
        defining->plus = false;
        defining->nolist = nolist;
        defining->in_progress = i;
        defining->nparam_min = defining->nparam_max = 0;
        defining->defaults = NULL;
        defining->dlist = NULL;
        defining->expansion = NULL;
        defining->next_active = istk->mstk;
        defining->rep_nest = tmp_defining;
        return DIRECTIVE_FOUND;

    case PP_ENDREP:
        if (!defining || defining->name) {
            error(ERR_NONFATAL, "`%%endrep': no matching `%%rep'");
            return DIRECTIVE_FOUND;
        }

        /*
         * Now we have a "macro" defined - although it has no name
         * and we won't be entering it in the hash tables - we must
         * push a macro-end marker for it on to istk->expansion.
         * After that, it will take care of propagating itself (a
         * macro-end marker line for a macro which is really a %rep
         * block will cause the macro to be re-expanded, complete
         * with another macro-end marker to ensure the process
         * continues) until the whole expansion is forcibly removed
         * from istk->expansion by a %exitrep.
         */
        l = nasm_malloc(sizeof(Line));
        l->next = istk->expansion;
        l->finishes = defining;
        l->first = NULL;
        istk->expansion = l;

        istk->mstk = defining;

        list->uplevel(defining->nolist ? LIST_MACRO_NOLIST : LIST_MACRO);
        tmp_defining = defining;
        defining = defining->rep_nest;
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_EXITREP:
        /*
         * We must search along istk->expansion until we hit a
         * macro-end marker for a macro with no name. Then we set
         * its `in_progress' flag to 0.
         */
        for (l = istk->expansion; l; l = l->next)
            if (l->finishes && !l->finishes->name)
                break;

        if (l)
            l->finishes->in_progress = 0;
        else
            error(ERR_NONFATAL, "`%%exitrep' not within `%%rep' block");
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_XDEFINE:
    case PP_IXDEFINE:
    case PP_DEFINE:
    case PP_IDEFINE:
        tline = tline->next;
        skip_white_(tline);
        tline = expand_id(tline);
        if (!tline || (tline->type != TOK_ID &&
                       (tline->type != TOK_PREPROC_ID ||
                        tline->text[1] != '$'))) {
            error(ERR_NONFATAL,
                  "`%%%s%sdefine' expects a macro identifier",
                  ((i == PP_IDEFINE || i == PP_IXDEFINE) ? "i" : ""),
                  ((i == PP_XDEFINE || i == PP_IXDEFINE) ? "x" : ""));
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }

        ctx = get_ctx(tline->text, false);

        mname = tline->text;
        last = tline;
        param_start = tline = tline->next;
        nparam = 0;

        /* Expand the macro definition now for %xdefine and %ixdefine */
        if ((i == PP_XDEFINE) || (i == PP_IXDEFINE))
            tline = expand_smacro(tline);

        if (tok_is_(tline, "(")) {
            /*
             * This macro has parameters.
             */

            tline = tline->next;
            while (1) {
                skip_white_(tline);
                if (!tline) {
                    error(ERR_NONFATAL, "parameter identifier expected");
                    free_tlist(origline);
                    return DIRECTIVE_FOUND;
                }
                if (tline->type != TOK_ID) {
                    error(ERR_NONFATAL,
                          "`%s': parameter identifier expected",
                          tline->text);
                    free_tlist(origline);
                    return DIRECTIVE_FOUND;
                }
                tline->type = TOK_SMAC_PARAM + nparam++;
                tline = tline->next;
                skip_white_(tline);
                if (tok_is_(tline, ",")) {
                    tline = tline->next;
                    continue;
                }
                if (!tok_is_(tline, ")")) {
                    error(ERR_NONFATAL,
                          "`)' expected to terminate macro template");
                    free_tlist(origline);
                    return DIRECTIVE_FOUND;
                }
                break;
            }
            last = tline;
            tline = tline->next;
        }
        if (tok_type_(tline, TOK_WHITESPACE))
            last = tline, tline = tline->next;
        macro_start = NULL;
        last->next = NULL;
        t = tline;
        while (t) {
            if (t->type == TOK_ID) {
                for (tt = param_start; tt; tt = tt->next)
                    if (tt->type >= TOK_SMAC_PARAM &&
                        !strcmp(tt->text, t->text))
                        t->type = tt->type;
            }
            tt = t->next;
            t->next = macro_start;
            macro_start = t;
            t = tt;
        }
        /*
         * Good. We now have a macro name, a parameter count, and a
         * token list (in reverse order) for an expansion. We ought
         * to be OK just to create an SMacro, store it, and let
         * free_tlist have the rest of the line (which we have
         * carefully re-terminated after chopping off the expansion
         * from the end).
         */
        if (smacro_defined(ctx, mname, nparam, &smac, i == PP_DEFINE)) {
            if (!smac) {
                error(ERR_WARNING,
                      "single-line macro `%s' defined both with and"
                      " without parameters", mname);
                free_tlist(origline);
                free_tlist(macro_start);
                return DIRECTIVE_FOUND;
            } else {
                /*
                 * We're redefining, so we have to take over an
                 * existing SMacro structure. This means freeing
                 * what was already in it.
                 */
                nasm_free(smac->name);
                free_tlist(smac->expansion);
            }
        } else {
	    if (!ctx)
		smhead = (SMacro **) hash_findi_add(smacros, mname);
	    else
		smhead = &ctx->localmac;

            smac = nasm_malloc(sizeof(SMacro));
            smac->next = *smhead;
            *smhead = smac;
        }
        smac->name = nasm_strdup(mname);
        smac->casesense = ((i == PP_DEFINE) || (i == PP_XDEFINE));
        smac->nparam = nparam;
        smac->expansion = macro_start;
        smac->in_progress = false;
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_UNDEF:
        tline = tline->next;
        skip_white_(tline);
        tline = expand_id(tline);
        if (!tline || (tline->type != TOK_ID &&
                       (tline->type != TOK_PREPROC_ID ||
                        tline->text[1] != '$'))) {
            error(ERR_NONFATAL, "`%%undef' expects a macro identifier");
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }
        if (tline->next) {
            error(ERR_WARNING,
                  "trailing garbage after macro name ignored");
        }

        /* Find the context that symbol belongs to */
        ctx = get_ctx(tline->text, false);
        if (!ctx)
            smhead = (SMacro **) hash_findi(smacros, tline->text, NULL);
        else
            smhead = &ctx->localmac;

	if (smhead) {
	    SMacro *s, **sp;

	    mname = tline->text;
	    last = tline;
	    last->next = NULL;
	    
	    /*
	     * We now have a macro name... go hunt for it.
	     */
	    sp = smhead;
	    while ((s = *sp) != NULL) {
		if (!mstrcmp(s->name, tline->text, s->casesense)) {
		    *sp = s->next;
		    nasm_free(s->name);
		    free_tlist(s->expansion);
		    nasm_free(s);
		} else {
		    sp = &s->next;
		}
	    }
	    free_tlist(origline);
	}
        return DIRECTIVE_FOUND;

    case PP_STRLEN:
        tline = tline->next;
        skip_white_(tline);
        tline = expand_id(tline);
        if (!tline || (tline->type != TOK_ID &&
                       (tline->type != TOK_PREPROC_ID ||
                        tline->text[1] != '$'))) {
            error(ERR_NONFATAL,
                  "`%%strlen' expects a macro identifier as first parameter");
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }
        ctx = get_ctx(tline->text, false);

        mname = tline->text;
        last = tline;
        tline = expand_smacro(tline->next);
        last->next = NULL;

        t = tline;
        while (tok_type_(t, TOK_WHITESPACE))
            t = t->next;
        /* t should now point to the string */
        if (t->type != TOK_STRING) {
            error(ERR_NONFATAL,
                  "`%%strlen` requires string as second parameter");
            free_tlist(tline);
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }

        macro_start = nasm_malloc(sizeof(*macro_start));
        macro_start->next = NULL;
        make_tok_num(macro_start, strlen(t->text) - 2);
        macro_start->mac = NULL;

        /*
         * We now have a macro name, an implicit parameter count of
         * zero, and a numeric token to use as an expansion. Create
         * and store an SMacro.
         */
        if (smacro_defined(ctx, mname, 0, &smac, i == PP_STRLEN)) {
            if (!smac)
                error(ERR_WARNING,
                      "single-line macro `%s' defined both with and"
                      " without parameters", mname);
            else {
                /*
                 * We're redefining, so we have to take over an
                 * existing SMacro structure. This means freeing
                 * what was already in it.
                 */
                nasm_free(smac->name);
                free_tlist(smac->expansion);
            }
        } else {
	    if (!ctx)
		smhead = (SMacro **) hash_findi_add(smacros, mname);
	    else
		smhead = &ctx->localmac;

            smac = nasm_malloc(sizeof(SMacro));
            smac->next = *smhead;
            *smhead = smac;
        }
        smac->name = nasm_strdup(mname);
        smac->casesense = (i == PP_STRLEN);
        smac->nparam = 0;
        smac->expansion = macro_start;
        smac->in_progress = false;
        free_tlist(tline);
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_SUBSTR:
        tline = tline->next;
        skip_white_(tline);
        tline = expand_id(tline);
        if (!tline || (tline->type != TOK_ID &&
                       (tline->type != TOK_PREPROC_ID ||
                        tline->text[1] != '$'))) {
            error(ERR_NONFATAL,
                  "`%%substr' expects a macro identifier as first parameter");
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }
        ctx = get_ctx(tline->text, false);

        mname = tline->text;
        last = tline;
        tline = expand_smacro(tline->next);
        last->next = NULL;

        t = tline->next;
        while (tok_type_(t, TOK_WHITESPACE))
            t = t->next;

        /* t should now point to the string */
        if (t->type != TOK_STRING) {
            error(ERR_NONFATAL,
                  "`%%substr` requires string as second parameter");
            free_tlist(tline);
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }

        tt = t->next;
        tptr = &tt;
        tokval.t_type = TOKEN_INVALID;
        evalresult =
            evaluate(ppscan, tptr, &tokval, NULL, pass, error, NULL);
        if (!evalresult) {
            free_tlist(tline);
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }
        if (!is_simple(evalresult)) {
            error(ERR_NONFATAL, "non-constant value given to `%%substr`");
            free_tlist(tline);
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }

        macro_start = nasm_malloc(sizeof(*macro_start));
        macro_start->next = NULL;
        macro_start->text = nasm_strdup("'''");
        if (evalresult->value > 0
            && evalresult->value < strlen(t->text) - 1) {
            macro_start->text[1] = t->text[evalresult->value];
        } else {
            macro_start->text[2] = '\0';
        }
        macro_start->type = TOK_STRING;
        macro_start->mac = NULL;

        /*
         * We now have a macro name, an implicit parameter count of
         * zero, and a numeric token to use as an expansion. Create
         * and store an SMacro.
         */
        if (smacro_defined(ctx, mname, 0, &smac, i == PP_SUBSTR)) {
            if (!smac)
                error(ERR_WARNING,
                      "single-line macro `%s' defined both with and"
                      " without parameters", mname);
            else {
                /*
                 * We're redefining, so we have to take over an
                 * existing SMacro structure. This means freeing
                 * what was already in it.
                 */
                nasm_free(smac->name);
                free_tlist(smac->expansion);
            }
        } else {
	    if (!ctx)
		smhead = (SMacro **) hash_findi_add(smacros, tline->text);
	    else
		smhead = &ctx->localmac;

            smac = nasm_malloc(sizeof(SMacro));
            smac->next = *smhead;
            *smhead = smac;
        }
        smac->name = nasm_strdup(mname);
        smac->casesense = (i == PP_SUBSTR);
        smac->nparam = 0;
        smac->expansion = macro_start;
        smac->in_progress = false;
        free_tlist(tline);
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_ASSIGN:
    case PP_IASSIGN:
        tline = tline->next;
        skip_white_(tline);
        tline = expand_id(tline);
        if (!tline || (tline->type != TOK_ID &&
                       (tline->type != TOK_PREPROC_ID ||
                        tline->text[1] != '$'))) {
            error(ERR_NONFATAL,
                  "`%%%sassign' expects a macro identifier",
                  (i == PP_IASSIGN ? "i" : ""));
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }
        ctx = get_ctx(tline->text, false);

        mname = tline->text;
        last = tline;
        tline = expand_smacro(tline->next);
        last->next = NULL;

        t = tline;
        tptr = &t;
        tokval.t_type = TOKEN_INVALID;
        evalresult =
            evaluate(ppscan, tptr, &tokval, NULL, pass, error, NULL);
        free_tlist(tline);
        if (!evalresult) {
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }

        if (tokval.t_type)
            error(ERR_WARNING,
                  "trailing garbage after expression ignored");

        if (!is_simple(evalresult)) {
            error(ERR_NONFATAL,
                  "non-constant value given to `%%%sassign'",
                  (i == PP_IASSIGN ? "i" : ""));
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }

        macro_start = nasm_malloc(sizeof(*macro_start));
        macro_start->next = NULL;
        make_tok_num(macro_start, reloc_value(evalresult));
        macro_start->mac = NULL;

        /*
         * We now have a macro name, an implicit parameter count of
         * zero, and a numeric token to use as an expansion. Create
         * and store an SMacro.
         */
        if (smacro_defined(ctx, mname, 0, &smac, i == PP_ASSIGN)) {
            if (!smac)
                error(ERR_WARNING,
                      "single-line macro `%s' defined both with and"
                      " without parameters", mname);
            else {
                /*
                 * We're redefining, so we have to take over an
                 * existing SMacro structure. This means freeing
                 * what was already in it.
                 */
                nasm_free(smac->name);
                free_tlist(smac->expansion);
            }
        } else {
	    if (!ctx)
		smhead = (SMacro **) hash_findi_add(smacros, mname);
	    else
		smhead = &ctx->localmac;

            smac = nasm_malloc(sizeof(SMacro));
            smac->next = *smhead;
            *smhead = smac;
        }
        smac->name = nasm_strdup(mname);
        smac->casesense = (i == PP_ASSIGN);
        smac->nparam = 0;
        smac->expansion = macro_start;
        smac->in_progress = false;
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    case PP_LINE:
        /*
         * Syntax is `%line nnn[+mmm] [filename]'
         */
        tline = tline->next;
        skip_white_(tline);
        if (!tok_type_(tline, TOK_NUMBER)) {
            error(ERR_NONFATAL, "`%%line' expects line number");
            free_tlist(origline);
            return DIRECTIVE_FOUND;
        }
        k = readnum(tline->text, &err);
        m = 1;
        tline = tline->next;
        if (tok_is_(tline, "+")) {
            tline = tline->next;
            if (!tok_type_(tline, TOK_NUMBER)) {
                error(ERR_NONFATAL, "`%%line' expects line increment");
                free_tlist(origline);
                return DIRECTIVE_FOUND;
            }
            m = readnum(tline->text, &err);
            tline = tline->next;
        }
        skip_white_(tline);
        src_set_linnum(k);
        istk->lineinc = m;
        if (tline) {
            nasm_free(src_set_fname(detoken(tline, false)));
        }
        free_tlist(origline);
        return DIRECTIVE_FOUND;

    default:
        error(ERR_FATAL,
              "preprocessor directive `%s' not yet implemented",
              pp_directives[i]);
        break;
    }
    return DIRECTIVE_FOUND;
}

/*
 * Ensure that a macro parameter contains a condition code and
 * nothing else. Return the condition code index if so, or -1
 * otherwise.
 */
static int find_cc(Token * t)
{
    Token *tt;
    int i, j, k, m;

    if (!t)
	    return -1;		/* Probably a %+ without a space */

    skip_white_(t);
    if (t->type != TOK_ID)
        return -1;
    tt = t->next;
    skip_white_(tt);
    if (tt && (tt->type != TOK_OTHER || strcmp(tt->text, ",")))
        return -1;

    i = -1;
    j = elements(conditions);
    while (j - i > 1) {
        k = (j + i) / 2;
        m = nasm_stricmp(t->text, conditions[k]);
        if (m == 0) {
            i = k;
            j = -2;
            break;
        } else if (m < 0) {
            j = k;
        } else
            i = k;
    }
    if (j != -2)
        return -1;
    return i;
}

/*
 * Expand MMacro-local things: parameter references (%0, %n, %+n,
 * %-n) and MMacro-local identifiers (%%foo).
 */
static Token *expand_mmac_params(Token * tline)
{
    Token *t, *tt, **tail, *thead;

    tail = &thead;
    thead = NULL;

    while (tline) {
        if (tline->type == TOK_PREPROC_ID &&
            (((tline->text[1] == '+' || tline->text[1] == '-')
              && tline->text[2]) || tline->text[1] == '%'
             || (tline->text[1] >= '0' && tline->text[1] <= '9'))) {
            char *text = NULL;
            int type = 0, cc;   /* type = 0 to placate optimisers */
            char tmpbuf[30];
            unsigned int n;
	    int i;
            MMacro *mac;

            t = tline;
            tline = tline->next;

            mac = istk->mstk;
            while (mac && !mac->name)   /* avoid mistaking %reps for macros */
                mac = mac->next_active;
            if (!mac)
                error(ERR_NONFATAL, "`%s': not in a macro call", t->text);
            else
                switch (t->text[1]) {
                    /*
                     * We have to make a substitution of one of the
                     * forms %1, %-1, %+1, %%foo, %0.
                     */
                case '0':
                    type = TOK_NUMBER;
                    snprintf(tmpbuf, sizeof(tmpbuf), "%d", mac->nparam);
                    text = nasm_strdup(tmpbuf);
                    break;
                case '%':
                    type = TOK_ID;
                    snprintf(tmpbuf, sizeof(tmpbuf), "..@%"PRIu32".",
                             mac->unique);
                    text = nasm_strcat(tmpbuf, t->text + 2);
                    break;
                case '-':
                    n = atoi(t->text + 2) - 1;
                    if (n >= mac->nparam)
                        tt = NULL;
                    else {
                        if (mac->nparam > 1)
                            n = (n + mac->rotate) % mac->nparam;
                        tt = mac->params[n];
                    }
                    cc = find_cc(tt);
                    if (cc == -1) {
                        error(ERR_NONFATAL,
                              "macro parameter %d is not a condition code",
                              n + 1);
                        text = NULL;
                    } else {
                        type = TOK_ID;
                        if (inverse_ccs[cc] == -1) {
                            error(ERR_NONFATAL,
                                  "condition code `%s' is not invertible",
                                  conditions[cc]);
                            text = NULL;
                        } else
                            text =
                                nasm_strdup(conditions[inverse_ccs[cc]]);
                    }
                    break;
                case '+':
                    n = atoi(t->text + 2) - 1;
                    if (n >= mac->nparam)
                        tt = NULL;
                    else {
                        if (mac->nparam > 1)
                            n = (n + mac->rotate) % mac->nparam;
                        tt = mac->params[n];
                    }
                    cc = find_cc(tt);
                    if (cc == -1) {
                        error(ERR_NONFATAL,
                              "macro parameter %d is not a condition code",
                              n + 1);
                        text = NULL;
                    } else {
                        type = TOK_ID;
                        text = nasm_strdup(conditions[cc]);
                    }
                    break;
                default:
                    n = atoi(t->text + 1) - 1;
                    if (n >= mac->nparam)
                        tt = NULL;
                    else {
                        if (mac->nparam > 1)
                            n = (n + mac->rotate) % mac->nparam;
                        tt = mac->params[n];
                    }
                    if (tt) {
                        for (i = 0; i < mac->paramlen[n]; i++) {
                            *tail = new_Token(NULL, tt->type, tt->text, 0);
                            tail = &(*tail)->next;
                            tt = tt->next;
                        }
                    }
                    text = NULL;        /* we've done it here */
                    break;
                }
            if (!text) {
                delete_Token(t);
            } else {
                *tail = t;
                tail = &t->next;
                t->type = type;
                nasm_free(t->text);
                t->text = text;
                t->mac = NULL;
            }
            continue;
        } else {
            t = *tail = tline;
            tline = tline->next;
            t->mac = NULL;
            tail = &t->next;
        }
    }
    *tail = NULL;
    t = thead;
    for (; t && (tt = t->next) != NULL; t = t->next)
        switch (t->type) {
        case TOK_WHITESPACE:
            if (tt->type == TOK_WHITESPACE) {
                t->next = delete_Token(tt);
            }
            break;
        case TOK_ID:
            if (tt->type == TOK_ID || tt->type == TOK_NUMBER) {
                char *tmp = nasm_strcat(t->text, tt->text);
                nasm_free(t->text);
                t->text = tmp;
                t->next = delete_Token(tt);
            }
            break;
        case TOK_NUMBER:
            if (tt->type == TOK_NUMBER) {
                char *tmp = nasm_strcat(t->text, tt->text);
                nasm_free(t->text);
                t->text = tmp;
                t->next = delete_Token(tt);
            }
            break;
	default:
	    break;
        }

    return thead;
}

/*
 * Expand all single-line macro calls made in the given line.
 * Return the expanded version of the line. The original is deemed
 * to be destroyed in the process. (In reality we'll just move
 * Tokens from input to output a lot of the time, rather than
 * actually bothering to destroy and replicate.)
 */
static Token *expand_smacro(Token * tline)
{
    Token *t, *tt, *mstart, **tail, *thead;
    SMacro *head = NULL, *m;
    Token **params;
    int *paramsize;
    unsigned int nparam, sparam;
    int brackets, rescan;
    Token *org_tline = tline;
    Context *ctx;
    char *mname;

    /*
     * Trick: we should avoid changing the start token pointer since it can
     * be contained in "next" field of other token. Because of this
     * we allocate a copy of first token and work with it; at the end of
     * routine we copy it back
     */
    if (org_tline) {
        tline =
            new_Token(org_tline->next, org_tline->type, org_tline->text,
                      0);
        tline->mac = org_tline->mac;
        nasm_free(org_tline->text);
        org_tline->text = NULL;
    }

  again:
    tail = &thead;
    thead = NULL;

    while (tline) {             /* main token loop */
        if ((mname = tline->text)) {
            /* if this token is a local macro, look in local context */
            if (tline->type == TOK_ID || tline->type == TOK_PREPROC_ID)
                ctx = get_ctx(mname, true);
            else
                ctx = NULL;
            if (!ctx) {
		head = (SMacro *) hash_findix(smacros, mname);
	    } else {
                head = ctx->localmac;
	    }
            /*
             * We've hit an identifier. As in is_mmacro below, we first
             * check whether the identifier is a single-line macro at
             * all, then think about checking for parameters if
             * necessary.
             */
	    for (m = head; m; m = m->next)
		if (!mstrcmp(m->name, mname, m->casesense))
		    break;
	    if (m) {
		mstart = tline;
		params = NULL;
		paramsize = NULL;
		if (m->nparam == 0) {
		    /*
		     * Simple case: the macro is parameterless. Discard the
		     * one token that the macro call took, and push the
		     * expansion back on the to-do stack.
		     */
		    if (!m->expansion) {
			if (!strcmp("__FILE__", m->name)) {
			    int32_t num = 0;
			    src_get(&num, &(tline->text));
			    nasm_quote(&(tline->text));
			    tline->type = TOK_STRING;
			    continue;
			}
			if (!strcmp("__LINE__", m->name)) {
			    nasm_free(tline->text);
			    make_tok_num(tline, src_get_linnum());
			    continue;
			}
			if (!strcmp("__BITS__", m->name)) {
			    nasm_free(tline->text);
			    make_tok_num(tline, globalbits);
                            continue;
			}
			tline = delete_Token(tline);
			continue;
		    }
		} else {
		    /*
		     * Complicated case: at least one macro with this name
                     * exists and takes parameters. We must find the
                     * parameters in the call, count them, find the SMacro
                     * that corresponds to that form of the macro call, and
                     * substitute for the parameters when we expand. What a
                     * pain.
                     */
                    /*tline = tline->next;
                       skip_white_(tline); */
                    do {
                        t = tline->next;
                        while (tok_type_(t, TOK_SMAC_END)) {
                            t->mac->in_progress = false;
                            t->text = NULL;
                            t = tline->next = delete_Token(t);
                        }
                        tline = t;
                    } while (tok_type_(tline, TOK_WHITESPACE));
                    if (!tok_is_(tline, "(")) {
                        /*
                         * This macro wasn't called with parameters: ignore
                         * the call. (Behaviour borrowed from gnu cpp.)
                         */
                        tline = mstart;
                        m = NULL;
                    } else {
                        int paren = 0;
                        int white = 0;
                        brackets = 0;
                        nparam = 0;
                        sparam = PARAM_DELTA;
                        params = nasm_malloc(sparam * sizeof(Token *));
                        params[0] = tline->next;
                        paramsize = nasm_malloc(sparam * sizeof(int));
                        paramsize[0] = 0;
                        while (true) {  /* parameter loop */
                            /*
                             * For some unusual expansions
                             * which concatenates function call
                             */
                            t = tline->next;
                            while (tok_type_(t, TOK_SMAC_END)) {
                                t->mac->in_progress = false;
                                t->text = NULL;
                                t = tline->next = delete_Token(t);
                            }
                            tline = t;

                            if (!tline) {
                                error(ERR_NONFATAL,
                                      "macro call expects terminating `)'");
                                break;
                            }
                            if (tline->type == TOK_WHITESPACE
                                && brackets <= 0) {
                                if (paramsize[nparam])
                                    white++;
                                else
                                    params[nparam] = tline->next;
                                continue;       /* parameter loop */
                            }
                            if (tline->type == TOK_OTHER
                                && tline->text[1] == 0) {
                                char ch = tline->text[0];
                                if (ch == ',' && !paren && brackets <= 0) {
                                    if (++nparam >= sparam) {
                                        sparam += PARAM_DELTA;
                                        params = nasm_realloc(params,
                                                              sparam *
                                                              sizeof(Token
                                                                     *));
                                        paramsize =
                                            nasm_realloc(paramsize,
                                                         sparam *
                                                         sizeof(int));
                                    }
                                    params[nparam] = tline->next;
                                    paramsize[nparam] = 0;
                                    white = 0;
                                    continue;   /* parameter loop */
                                }
                                if (ch == '{' &&
                                    (brackets > 0 || (brackets == 0 &&
                                                      !paramsize[nparam])))
                                {
                                    if (!(brackets++)) {
                                        params[nparam] = tline->next;
                                        continue;       /* parameter loop */
                                    }
                                }
                                if (ch == '}' && brackets > 0)
                                    if (--brackets == 0) {
                                        brackets = -1;
                                        continue;       /* parameter loop */
                                    }
                                if (ch == '(' && !brackets)
                                    paren++;
                                if (ch == ')' && brackets <= 0)
                                    if (--paren < 0)
                                        break;
                            }
                            if (brackets < 0) {
                                brackets = 0;
                                error(ERR_NONFATAL, "braces do not "
                                      "enclose all of macro parameter");
                            }
                            paramsize[nparam] += white + 1;
                            white = 0;
                        }       /* parameter loop */
                        nparam++;
                        while (m && (m->nparam != nparam ||
                                     mstrcmp(m->name, mname,
                                             m->casesense)))
                            m = m->next;
                        if (!m)
                            error(ERR_WARNING | ERR_WARN_MNP,
                                  "macro `%s' exists, "
                                  "but not taking %d parameters",
                                  mstart->text, nparam);
                    }
                }
                if (m && m->in_progress)
                    m = NULL;
                if (!m) {       /* in progess or didn't find '(' or wrong nparam */
                    /* 
                     * Design question: should we handle !tline, which
                     * indicates missing ')' here, or expand those
                     * macros anyway, which requires the (t) test a few
                     * lines down?  
                     */
                    nasm_free(params);
                    nasm_free(paramsize);
                    tline = mstart;
                } else {
                    /*
                     * Expand the macro: we are placed on the last token of the
                     * call, so that we can easily split the call from the
                     * following tokens. We also start by pushing an SMAC_END
                     * token for the cycle removal.
                     */
                    t = tline;
                    if (t) {
                        tline = t->next;
                        t->next = NULL;
                    }
                    tt = new_Token(tline, TOK_SMAC_END, NULL, 0);
                    tt->mac = m;
                    m->in_progress = true;
                    tline = tt;
                    for (t = m->expansion; t; t = t->next) {
                        if (t->type >= TOK_SMAC_PARAM) {
                            Token *pcopy = tline, **ptail = &pcopy;
                            Token *ttt, *pt;
                            int i;

                            ttt = params[t->type - TOK_SMAC_PARAM];
                            for (i = paramsize[t->type - TOK_SMAC_PARAM];
                                 --i >= 0;) {
                                pt = *ptail =
                                    new_Token(tline, ttt->type, ttt->text,
                                              0);
                                ptail = &pt->next;
                                ttt = ttt->next;
                            }
                            tline = pcopy;
                        } else {
                            tt = new_Token(tline, t->type, t->text, 0);
                            tline = tt;
                        }
                    }

                    /*
                     * Having done that, get rid of the macro call, and clean
                     * up the parameters.
                     */
                    nasm_free(params);
                    nasm_free(paramsize);
                    free_tlist(mstart);
                    continue;   /* main token loop */
                }
            }
        }

        if (tline->type == TOK_SMAC_END) {
            tline->mac->in_progress = false;
            tline = delete_Token(tline);
        } else {
            t = *tail = tline;
            tline = tline->next;
            t->mac = NULL;
            t->next = NULL;
            tail = &t->next;
        }
    }

    /*
     * Now scan the entire line and look for successive TOK_IDs that resulted
     * after expansion (they can't be produced by tokenize()). The successive
     * TOK_IDs should be concatenated.
     * Also we look for %+ tokens and concatenate the tokens before and after
     * them (without white spaces in between).
     */
    t = thead;
    rescan = 0;
    while (t) {
        while (t && t->type != TOK_ID && t->type != TOK_PREPROC_ID)
            t = t->next;
        if (!t || !t->next)
            break;
        if (t->next->type == TOK_ID ||
            t->next->type == TOK_PREPROC_ID ||
            t->next->type == TOK_NUMBER) {
            char *p = nasm_strcat(t->text, t->next->text);
            nasm_free(t->text);
            t->next = delete_Token(t->next);
            t->text = p;
            rescan = 1;
        } else if (t->next->type == TOK_WHITESPACE && t->next->next &&
                   t->next->next->type == TOK_PREPROC_ID &&
                   strcmp(t->next->next->text, "%+") == 0) {
            /* free the next whitespace, the %+ token and next whitespace */
            int i;
            for (i = 1; i <= 3; i++) {
                if (!t->next
                    || (i != 2 && t->next->type != TOK_WHITESPACE))
                    break;
                t->next = delete_Token(t->next);
            }                   /* endfor */
        } else
            t = t->next;
    }
    /* If we concatenaded something, re-scan the line for macros */
    if (rescan) {
        tline = thead;
        goto again;
    }

    if (org_tline) {
        if (thead) {
            *org_tline = *thead;
            /* since we just gave text to org_line, don't free it */
            thead->text = NULL;
            delete_Token(thead);
        } else {
            /* the expression expanded to empty line;
               we can't return NULL for some reasons
               we just set the line to a single WHITESPACE token. */
            memset(org_tline, 0, sizeof(*org_tline));
            org_tline->text = NULL;
            org_tline->type = TOK_WHITESPACE;
        }
        thead = org_tline;
    }

    return thead;
}

/*
 * Similar to expand_smacro but used exclusively with macro identifiers
 * right before they are fetched in. The reason is that there can be
 * identifiers consisting of several subparts. We consider that if there
 * are more than one element forming the name, user wants a expansion,
 * otherwise it will be left as-is. Example:
 *
 *	%define %$abc cde
 *
 * the identifier %$abc will be left as-is so that the handler for %define
 * will suck it and define the corresponding value. Other case:
 *
 *	%define _%$abc cde
 *
 * In this case user wants name to be expanded *before* %define starts
 * working, so we'll expand %$abc into something (if it has a value;
 * otherwise it will be left as-is) then concatenate all successive
 * PP_IDs into one.
 */
static Token *expand_id(Token * tline)
{
    Token *cur, *oldnext = NULL;

    if (!tline || !tline->next)
        return tline;

    cur = tline;
    while (cur->next &&
           (cur->next->type == TOK_ID ||
            cur->next->type == TOK_PREPROC_ID
            || cur->next->type == TOK_NUMBER))
        cur = cur->next;

    /* If identifier consists of just one token, don't expand */
    if (cur == tline)
        return tline;

    if (cur) {
        oldnext = cur->next;    /* Detach the tail past identifier */
        cur->next = NULL;       /* so that expand_smacro stops here */
    }

    tline = expand_smacro(tline);

    if (cur) {
        /* expand_smacro possibly changhed tline; re-scan for EOL */
        cur = tline;
        while (cur && cur->next)
            cur = cur->next;
        if (cur)
            cur->next = oldnext;
    }

    return tline;
}

/*
 * Determine whether the given line constitutes a multi-line macro
 * call, and return the MMacro structure called if so. Doesn't have
 * to check for an initial label - that's taken care of in
 * expand_mmacro - but must check numbers of parameters. Guaranteed
 * to be called with tline->type == TOK_ID, so the putative macro
 * name is easy to find.
 */
static MMacro *is_mmacro(Token * tline, Token *** params_array)
{
    MMacro *head, *m;
    Token **params;
    int nparam;

    head = (MMacro *) hash_findix(mmacros, tline->text);

    /*
     * Efficiency: first we see if any macro exists with the given
     * name. If not, we can return NULL immediately. _Then_ we
     * count the parameters, and then we look further along the
     * list if necessary to find the proper MMacro.
     */
    for (m = head; m; m = m->next)
        if (!mstrcmp(m->name, tline->text, m->casesense))
            break;
    if (!m)
        return NULL;

    /*
     * OK, we have a potential macro. Count and demarcate the
     * parameters.
     */
    count_mmac_params(tline->next, &nparam, &params);

    /*
     * So we know how many parameters we've got. Find the MMacro
     * structure that handles this number.
     */
    while (m) {
        if (m->nparam_min <= nparam
            && (m->plus || nparam <= m->nparam_max)) {
            /*
             * This one is right. Just check if cycle removal
             * prohibits us using it before we actually celebrate...
             */
            if (m->in_progress) {
#if 0
                error(ERR_NONFATAL,
                      "self-reference in multi-line macro `%s'", m->name);
#endif
                nasm_free(params);
                return NULL;
            }
            /*
             * It's right, and we can use it. Add its default
             * parameters to the end of our list if necessary.
             */
            if (m->defaults && nparam < m->nparam_min + m->ndefs) {
                params =
                    nasm_realloc(params,
                                 ((m->nparam_min + m->ndefs +
                                   1) * sizeof(*params)));
                while (nparam < m->nparam_min + m->ndefs) {
                    params[nparam] = m->defaults[nparam - m->nparam_min];
                    nparam++;
                }
            }
            /*
             * If we've gone over the maximum parameter count (and
             * we're in Plus mode), ignore parameters beyond
             * nparam_max.
             */
            if (m->plus && nparam > m->nparam_max)
                nparam = m->nparam_max;
            /*
             * Then terminate the parameter list, and leave.
             */
            if (!params) {      /* need this special case */
                params = nasm_malloc(sizeof(*params));
                nparam = 0;
            }
            params[nparam] = NULL;
            *params_array = params;
            return m;
        }
        /*
         * This one wasn't right: look for the next one with the
         * same name.
         */
        for (m = m->next; m; m = m->next)
            if (!mstrcmp(m->name, tline->text, m->casesense))
                break;
    }

    /*
     * After all that, we didn't find one with the right number of
     * parameters. Issue a warning, and fail to expand the macro.
     */
    error(ERR_WARNING | ERR_WARN_MNP,
          "macro `%s' exists, but not taking %d parameters",
          tline->text, nparam);
    nasm_free(params);
    return NULL;
}

/*
 * Expand the multi-line macro call made by the given line, if
 * there is one to be expanded. If there is, push the expansion on
 * istk->expansion and return 1. Otherwise return 0.
 */
static int expand_mmacro(Token * tline)
{
    Token *startline = tline;
    Token *label = NULL;
    int dont_prepend = 0;
    Token **params, *t, *tt;
    MMacro *m;
    Line *l, *ll;
    int i, nparam, *paramlen;

    t = tline;
    skip_white_(t);
/*    if (!tok_type_(t, TOK_ID))  Lino 02/25/02 */
    if (!tok_type_(t, TOK_ID) && !tok_type_(t, TOK_PREPROC_ID))
        return 0;
    m = is_mmacro(t, &params);
    if (!m) {
        Token *last;
        /*
         * We have an id which isn't a macro call. We'll assume
         * it might be a label; we'll also check to see if a
         * colon follows it. Then, if there's another id after
         * that lot, we'll check it again for macro-hood.
         */
        label = last = t;
        t = t->next;
        if (tok_type_(t, TOK_WHITESPACE))
            last = t, t = t->next;
        if (tok_is_(t, ":")) {
            dont_prepend = 1;
            last = t, t = t->next;
            if (tok_type_(t, TOK_WHITESPACE))
                last = t, t = t->next;
        }
        if (!tok_type_(t, TOK_ID) || (m = is_mmacro(t, &params)) == NULL)
            return 0;
        last->next = NULL;
        tline = t;
    }

    /*
     * Fix up the parameters: this involves stripping leading and
     * trailing whitespace, then stripping braces if they are
     * present.
     */
    for (nparam = 0; params[nparam]; nparam++) ;
    paramlen = nparam ? nasm_malloc(nparam * sizeof(*paramlen)) : NULL;

    for (i = 0; params[i]; i++) {
        int brace = false;
        int comma = (!m->plus || i < nparam - 1);

        t = params[i];
        skip_white_(t);
        if (tok_is_(t, "{"))
            t = t->next, brace = true, comma = false;
        params[i] = t;
        paramlen[i] = 0;
        while (t) {
            if (comma && t->type == TOK_OTHER && !strcmp(t->text, ","))
                break;          /* ... because we have hit a comma */
            if (comma && t->type == TOK_WHITESPACE
                && tok_is_(t->next, ","))
                break;          /* ... or a space then a comma */
            if (brace && t->type == TOK_OTHER && !strcmp(t->text, "}"))
                break;          /* ... or a brace */
            t = t->next;
            paramlen[i]++;
        }
    }

    /*
     * OK, we have a MMacro structure together with a set of
     * parameters. We must now go through the expansion and push
     * copies of each Line on to istk->expansion. Substitution of
     * parameter tokens and macro-local tokens doesn't get done
     * until the single-line macro substitution process; this is
     * because delaying them allows us to change the semantics
     * later through %rotate.
     *
     * First, push an end marker on to istk->expansion, mark this
     * macro as in progress, and set up its invocation-specific
     * variables.
     */
    ll = nasm_malloc(sizeof(Line));
    ll->next = istk->expansion;
    ll->finishes = m;
    ll->first = NULL;
    istk->expansion = ll;

    m->in_progress = true;
    m->params = params;
    m->iline = tline;
    m->nparam = nparam;
    m->rotate = 0;
    m->paramlen = paramlen;
    m->unique = unique++;
    m->lineno = 0;

    m->next_active = istk->mstk;
    istk->mstk = m;

    for (l = m->expansion; l; l = l->next) {
        Token **tail;

        ll = nasm_malloc(sizeof(Line));
        ll->finishes = NULL;
        ll->next = istk->expansion;
        istk->expansion = ll;
        tail = &ll->first;

        for (t = l->first; t; t = t->next) {
            Token *x = t;
            if (t->type == TOK_PREPROC_ID &&
                t->text[1] == '0' && t->text[2] == '0') {
                dont_prepend = -1;
                x = label;
                if (!x)
                    continue;
            }
            tt = *tail = new_Token(NULL, x->type, x->text, 0);
            tail = &tt->next;
        }
        *tail = NULL;
    }

    /*
     * If we had a label, push it on as the first line of
     * the macro expansion.
     */
    if (label) {
        if (dont_prepend < 0)
            free_tlist(startline);
        else {
            ll = nasm_malloc(sizeof(Line));
            ll->finishes = NULL;
            ll->next = istk->expansion;
            istk->expansion = ll;
            ll->first = startline;
            if (!dont_prepend) {
                while (label->next)
                    label = label->next;
                label->next = tt = new_Token(NULL, TOK_OTHER, ":", 0);
            }
        }
    }

    list->uplevel(m->nolist ? LIST_MACRO_NOLIST : LIST_MACRO);

    return 1;
}

/*
 * Since preprocessor always operate only on the line that didn't
 * arrived yet, we should always use ERR_OFFBY1. Also since user
 * won't want to see same error twice (preprocessing is done once
 * per pass) we will want to show errors only during pass one.
 */
static void error(int severity, const char *fmt, ...)
{
    va_list arg;
    char buff[1024];

    /* If we're in a dead branch of IF or something like it, ignore the error */
    if (istk && istk->conds && !emitting(istk->conds->state))
        return;

    va_start(arg, fmt);
    vsnprintf(buff, sizeof(buff), fmt, arg);
    va_end(arg);

    if (istk && istk->mstk && istk->mstk->name)
        _error(severity | ERR_PASS1, "(%s:%d) %s", istk->mstk->name,
               istk->mstk->lineno, buff);
    else
        _error(severity | ERR_PASS1, "%s", buff);
}

static void
pp_reset(char *file, int apass, efunc errfunc, evalfunc eval,
         ListGen * listgen)
{
    _error = errfunc;
    cstk = NULL;
    istk = nasm_malloc(sizeof(Include));
    istk->next = NULL;
    istk->conds = NULL;
    istk->expansion = NULL;
    istk->mstk = NULL;
    istk->fp = fopen(file, "r");
    istk->fname = NULL;
    src_set_fname(nasm_strdup(file));
    src_set_linnum(0);
    istk->lineinc = 1;
    if (!istk->fp)
        error(ERR_FATAL | ERR_NOFILE, "unable to open input file `%s'",
              file);
    defining = NULL;
    init_macros();
    unique = 0;
    if (tasm_compatible_mode) {
        stdmacpos = stdmac;
    } else {
        stdmacpos = &stdmac[TASM_MACRO_COUNT];
    }
    any_extrastdmac = (extrastdmac != NULL);
    list = listgen;
    evaluate = eval;
    pass = apass;
}

static char *pp_getline(void)
{
    char *line;
    Token *tline;

    while (1) {
        /*
         * Fetch a tokenized line, either from the macro-expansion
         * buffer or from the input file.
         */
        tline = NULL;
        while (istk->expansion && istk->expansion->finishes) {
            Line *l = istk->expansion;
            if (!l->finishes->name && l->finishes->in_progress > 1) {
                Line *ll;

                /*
                 * This is a macro-end marker for a macro with no
                 * name, which means it's not really a macro at all
                 * but a %rep block, and the `in_progress' field is
                 * more than 1, meaning that we still need to
                 * repeat. (1 means the natural last repetition; 0
                 * means termination by %exitrep.) We have
                 * therefore expanded up to the %endrep, and must
                 * push the whole block on to the expansion buffer
                 * again. We don't bother to remove the macro-end
                 * marker: we'd only have to generate another one
                 * if we did.
                 */
                l->finishes->in_progress--;
                for (l = l->finishes->expansion; l; l = l->next) {
                    Token *t, *tt, **tail;

                    ll = nasm_malloc(sizeof(Line));
                    ll->next = istk->expansion;
                    ll->finishes = NULL;
                    ll->first = NULL;
                    tail = &ll->first;

                    for (t = l->first; t; t = t->next) {
                        if (t->text || t->type == TOK_WHITESPACE) {
                            tt = *tail =
                                new_Token(NULL, t->type, t->text, 0);
                            tail = &tt->next;
                        }
                    }

                    istk->expansion = ll;
                }
            } else {
                /*
                 * Check whether a `%rep' was started and not ended
                 * within this macro expansion. This can happen and
                 * should be detected. It's a fatal error because
                 * I'm too confused to work out how to recover
                 * sensibly from it.
                 */
                if (defining) {
                    if (defining->name)
                        error(ERR_PANIC,
                              "defining with name in expansion");
                    else if (istk->mstk->name)
                        error(ERR_FATAL,
                              "`%%rep' without `%%endrep' within"
                              " expansion of macro `%s'",
                              istk->mstk->name);
                }

                /*
                 * FIXME:  investigate the relationship at this point between
                 * istk->mstk and l->finishes
                 */
                {
                    MMacro *m = istk->mstk;
                    istk->mstk = m->next_active;
                    if (m->name) {
                        /*
                         * This was a real macro call, not a %rep, and
                         * therefore the parameter information needs to
                         * be freed.
                         */
                        nasm_free(m->params);
                        free_tlist(m->iline);
                        nasm_free(m->paramlen);
                        l->finishes->in_progress = false;
                    } else
                        free_mmacro(m);
                }
                istk->expansion = l->next;
                nasm_free(l);
                list->downlevel(LIST_MACRO);
            }
        }
        while (1) {             /* until we get a line we can use */

            if (istk->expansion) {      /* from a macro expansion */
                char *p;
                Line *l = istk->expansion;
                if (istk->mstk)
                    istk->mstk->lineno++;
                tline = l->first;
                istk->expansion = l->next;
                nasm_free(l);
                p = detoken(tline, false);
                list->line(LIST_MACRO, p);
                nasm_free(p);
                break;
            }
            line = read_line();
            if (line) {         /* from the current input file */
                line = prepreproc(line);
                tline = tokenize(line);
                nasm_free(line);
                break;
            }
            /*
             * The current file has ended; work down the istk
             */
            {
                Include *i = istk;
                fclose(i->fp);
                if (i->conds)
                    error(ERR_FATAL,
                          "expected `%%endif' before end of file");
                /* only set line and file name if there's a next node */
                if (i->next) {
                    src_set_linnum(i->lineno);
                    nasm_free(src_set_fname(i->fname));
                }
                istk = i->next;
                list->downlevel(LIST_INCLUDE);
                nasm_free(i);
                if (!istk)
                    return NULL;
            }
        }

        /*
         * We must expand MMacro parameters and MMacro-local labels
         * _before_ we plunge into directive processing, to cope
         * with things like `%define something %1' such as STRUC
         * uses. Unless we're _defining_ a MMacro, in which case
         * those tokens should be left alone to go into the
         * definition; and unless we're in a non-emitting
         * condition, in which case we don't want to meddle with
         * anything.
         */
        if (!defining && !(istk->conds && !emitting(istk->conds->state)))
            tline = expand_mmac_params(tline);

        /*
         * Check the line to see if it's a preprocessor directive.
         */
        if (do_directive(tline) == DIRECTIVE_FOUND) {
            continue;
        } else if (defining) {
            /*
             * We're defining a multi-line macro. We emit nothing
             * at all, and just
             * shove the tokenized line on to the macro definition.
             */
            Line *l = nasm_malloc(sizeof(Line));
            l->next = defining->expansion;
            l->first = tline;
            l->finishes = false;
            defining->expansion = l;
            continue;
        } else if (istk->conds && !emitting(istk->conds->state)) {
            /*
             * We're in a non-emitting branch of a condition block.
             * Emit nothing at all, not even a blank line: when we
             * emerge from the condition we'll give a line-number
             * directive so we keep our place correctly.
             */
            free_tlist(tline);
            continue;
        } else if (istk->mstk && !istk->mstk->in_progress) {
            /*
             * We're in a %rep block which has been terminated, so
             * we're walking through to the %endrep without
             * emitting anything. Emit nothing at all, not even a
             * blank line: when we emerge from the %rep block we'll
             * give a line-number directive so we keep our place
             * correctly.
             */
            free_tlist(tline);
            continue;
        } else {
            tline = expand_smacro(tline);
            if (!expand_mmacro(tline)) {
                /*
                 * De-tokenize the line again, and emit it.
                 */
                line = detoken(tline, true);
                free_tlist(tline);
                break;
            } else {
                continue;       /* expand_mmacro calls free_tlist */
            }
        }
    }

    return line;
}

static void pp_cleanup(int pass)
{
    if (defining) {
        error(ERR_NONFATAL, "end of file while still defining macro `%s'",
              defining->name);
        free_mmacro(defining);
    }
    while (cstk)
        ctx_pop();
    free_macros();
    while (istk) {
        Include *i = istk;
        istk = istk->next;
        fclose(i->fp);
        nasm_free(i->fname);
        nasm_free(i);
    }
    while (cstk)
        ctx_pop();
    if (pass == 0) {
        free_llist(predef);
        delete_Blocks();
    }
}

void pp_include_path(char *path)
{
    IncPath *i;

    i = nasm_malloc(sizeof(IncPath));
    i->path = path ? nasm_strdup(path) : NULL;
    i->next = NULL;

    if (ipath != NULL) {
        IncPath *j = ipath;
        while (j->next != NULL)
            j = j->next;
        j->next = i;
    } else {
        ipath = i;
    }
}

/*
 * added by alexfru:
 *
 * This function is used to "export" the include paths, e.g.
 * the paths specified in the '-I' command switch.
 * The need for such exporting is due to the 'incbin' directive,
 * which includes raw binary files (unlike '%include', which
 * includes text source files). It would be real nice to be
 * able to specify paths to search for incbin'ned files also.
 * So, this is a simple workaround.
 *
 * The function use is simple:
 *
 * The 1st call (with NULL argument) returns a pointer to the 1st path
 * (char** type) or NULL if none include paths available.
 *
 * All subsequent calls take as argument the value returned by this
 * function last. The return value is either the next path
 * (char** type) or NULL if the end of the paths list is reached.
 *
 * It is maybe not the best way to do things, but I didn't want
 * to export too much, just one or two functions and no types or
 * variables exported.
 *
 * Can't say I like the current situation with e.g. this path list either,
 * it seems to be never deallocated after creation...
 */
char **pp_get_include_path_ptr(char **pPrevPath)
{
/*   This macro returns offset of a member of a structure */
#define GetMemberOffset(StructType,MemberName)\
  ((size_t)&((StructType*)0)->MemberName)
    IncPath *i;

    if (pPrevPath == NULL) {
        if (ipath != NULL)
            return &ipath->path;
        else
            return NULL;
    }
    i = (IncPath *) ((char *)pPrevPath - GetMemberOffset(IncPath, path));
    i = i->next;
    if (i != NULL)
        return &i->path;
    else
        return NULL;
#undef GetMemberOffset
}

void pp_pre_include(char *fname)
{
    Token *inc, *space, *name;
    Line *l;

    name = new_Token(NULL, TOK_INTERNAL_STRING, fname, 0);
    space = new_Token(name, TOK_WHITESPACE, NULL, 0);
    inc = new_Token(space, TOK_PREPROC_ID, "%include", 0);

    l = nasm_malloc(sizeof(Line));
    l->next = predef;
    l->first = inc;
    l->finishes = false;
    predef = l;
}

void pp_pre_define(char *definition)
{
    Token *def, *space;
    Line *l;
    char *equals;

    equals = strchr(definition, '=');
    space = new_Token(NULL, TOK_WHITESPACE, NULL, 0);
    def = new_Token(space, TOK_PREPROC_ID, "%define", 0);
    if (equals)
        *equals = ' ';
    space->next = tokenize(definition);
    if (equals)
        *equals = '=';

    l = nasm_malloc(sizeof(Line));
    l->next = predef;
    l->first = def;
    l->finishes = false;
    predef = l;
}

void pp_pre_undefine(char *definition)
{
    Token *def, *space;
    Line *l;

    space = new_Token(NULL, TOK_WHITESPACE, NULL, 0);
    def = new_Token(space, TOK_PREPROC_ID, "%undef", 0);
    space->next = tokenize(definition);

    l = nasm_malloc(sizeof(Line));
    l->next = predef;
    l->first = def;
    l->finishes = false;
    predef = l;
}

/*
 * Added by Keith Kanios:
 *
 * This function is used to assist with "runtime" preprocessor
 * directives. (e.g. pp_runtime("%define __BITS__ 64");)
 *
 * ERRORS ARE IGNORED HERE, SO MAKE COMPLETELY SURE THAT YOU
 * PASS A VALID STRING TO THIS FUNCTION!!!!!
 */

void pp_runtime(char *definition)
{
    Token *def;
    
    def = tokenize(definition);
    if(do_directive(def) == NO_DIRECTIVE_FOUND)
        free_tlist(def);
        
}

void pp_extra_stdmac(const char **macros)
{
    extrastdmac = macros;
}

static void make_tok_num(Token * tok, int32_t val)
{
    char numbuf[20];
    snprintf(numbuf, sizeof(numbuf), "%"PRId32"", val);
    tok->text = nasm_strdup(numbuf);
    tok->type = TOK_NUMBER;
}

Preproc nasmpp = {
    pp_reset,
    pp_getline,
    pp_cleanup
};