Initial commit of all the NXT integration.

More like squashed history, contributors were:
 - Kai Ninomiya
 - Corentin Wallez
diff --git a/src/backend/common/Math.cpp b/src/backend/common/Math.cpp
new file mode 100644
index 0000000..483f524
--- /dev/null
+++ b/src/backend/common/Math.cpp
@@ -0,0 +1,52 @@
+// Copyright 2017 The NXT Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "Math.h"
+
+#include "Forward.h"
+
+namespace backend {
+
+    unsigned long ScanForward(unsigned long bits) {
+        ASSERT(bits != 0);
+        // TODO(cwallez@chromium.org): handle non-posix platforms
+        // unsigned long firstBitIndex = 0ul;
+        // unsigned char ret = _BitScanForward(&firstBitIndex, bits);
+        // ASSERT(ret != 0);
+        // return firstBitIndex;
+        return static_cast<unsigned long>(__builtin_ctzl(bits));
+    }
+
+    uint32_t Log2(uint32_t value) {
+        ASSERT(value != 0);
+        return 31 - __builtin_clz(value);
+    }
+
+    bool IsPowerOfTwo(size_t n) {
+        ASSERT(n != 0);
+        return (n & (n - 1)) == 0;
+    }
+
+    bool IsAligned(const void* ptr, size_t alignment) {
+        ASSERT(IsPowerOfTwo(alignment));
+        ASSERT(alignment != 0);
+        return (reinterpret_cast<intptr_t>(ptr) & (alignment - 1)) == 0;
+    }
+
+    void* AlignVoidPtr(void* ptr, size_t alignment) {
+        ASSERT(alignment != 0);
+        return reinterpret_cast<void*>((reinterpret_cast<intptr_t>(ptr) + (alignment - 1)) & ~(alignment - 1));
+    }
+
+}