Update to NSS 3.12.7 and NSPR 4.8.6....

nss/mozilla/nsprpub/pr/include/prbit.h

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (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.mozilla.org/MPL/
  *
  * Software distributed under the License is distributed on an "AS IS" basis,
@@ skipping 23 matching lines @@
  * the terms of any one of the MPL, the GPL or the LGPL.
  *
  * ***** END LICENSE BLOCK ***** */
 
 #ifndef prbit_h___
 #define prbit_h___
 
 #include "prtypes.h"
 PR_BEGIN_EXTERN_C
 
+/* replace compare/jump/add/shift sequence with x86 BSF/BSR instruction */
+#if defined(_WIN32) && (_MSC_VER >= 1300) && (defined(_M_IX86) || defined(_M_AMD64))
+  unsigned char _BitScanForward(unsigned long * Index, unsigned long Mask);
+  unsigned char _BitScanReverse(unsigned long * Index, unsigned long Mask);
+# pragma  intrinsic(_BitScanForward,_BitScanReverse)
+  __forceinline static int __prBitScanForward32(unsigned int val)
+  { 
+    unsigned long idx;
+    _BitScanForward(&idx, (unsigned long)val);
+    return( (int)idx );
+  }
+  __forceinline static int __prBitScanReverse32(unsigned int val)
+  {
+    unsigned long idx;
+    _BitScanReverse(&idx, (unsigned long)val);
+    return( (int)(31-idx) );
+  }
+# define pr_bitscan_ctz32(val)  __prBitScanForward32(val)
+# define pr_bitscan_clz32(val)  __prBitScanReverse32(val)
+# define  PR_HAVE_BUILTIN_BITSCAN32
+#elif ((__GNUC__ >= 4) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) && \
+       (defined(__i386__) || defined(__x86_64__) || defined(__arm__))
+# define pr_bitscan_ctz32(val)  __builtin_ctz(val)
+# define pr_bitscan_clz32(val)  __builtin_clz(val)
+# define  PR_HAVE_BUILTIN_BITSCAN32
+#endif /* MSVC || GCC */
+
 /*
 ** A prbitmap_t is a long integer that can be used for bitmaps
 */
 typedef unsigned long prbitmap_t;
 
 #define PR_TEST_BIT(_map,_bit) \
     ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] & (1L << ((_bit) & (PR_BITS_PER_LONG-1))))
 #define PR_SET_BIT(_map,_bit) \
     ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] |= (1L << ((_bit) & (PR_BITS_PER_LONG-1))))
 #define PR_CLEAR_BIT(_map,_bit) \
     ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] &= ~(1L << ((_bit) & (PR_BITS_PER_LONG-1))))
 
 /*
 ** Compute the log of the least power of 2 greater than or equal to n
 */
 NSPR_API(PRIntn) PR_CeilingLog2(PRUint32 i); 
 
 /*
 ** Compute the log of the greatest power of 2 less than or equal to n
 */
 NSPR_API(PRIntn) PR_FloorLog2(PRUint32 i); 
 
 /*
 ** Macro version of PR_CeilingLog2: Compute the log of the least power of
 ** 2 greater than or equal to _n. The result is returned in _log2.
 */
+#ifdef PR_HAVE_BUILTIN_BITSCAN32 
+#define PR_CEILING_LOG2(_log2,_n)      \
+  PR_BEGIN_MACRO                       \
+    PRUint32 j_ = (PRUint32)(_n);      \
+    (_log2) = (j_ <= 1 ? 0 : 32 - pr_bitscan_clz32(j_ - 1)); \
+  PR_END_MACRO
+#else
 #define PR_CEILING_LOG2(_log2,_n)   \
   PR_BEGIN_MACRO                    \
     PRUint32 j_ = (PRUint32)(_n);       \
     (_log2) = 0;                    \
     if ((j_) & ((j_)-1))            \
         (_log2) += 1;               \
     if ((j_) >> 16)                 \
         (_log2) += 16, (j_) >>= 16; \
     if ((j_) >> 8)                  \
         (_log2) += 8, (j_) >>= 8;   \
     if ((j_) >> 4)                  \
         (_log2) += 4, (j_) >>= 4;   \
     if ((j_) >> 2)                  \
         (_log2) += 2, (j_) >>= 2;   \
     if ((j_) >> 1)                  \
         (_log2) += 1;               \
   PR_END_MACRO
+#endif /* PR_HAVE_BUILTIN_BITSCAN32 */
 
 /*
 ** Macro version of PR_FloorLog2: Compute the log of the greatest power of
 ** 2 less than or equal to _n. The result is returned in _log2.
 **
 ** This is equivalent to finding the highest set bit in the word.
 */
+#ifdef PR_HAVE_BUILTIN_BITSCAN32
+#define PR_FLOOR_LOG2(_log2,_n)     \
+  PR_BEGIN_MACRO                    \
+    PRUint32 j_ = (PRUint32)(_n);   \
+    (_log2) = 31 - pr_bitscan_clz32((j_) | 1); \
+  PR_END_MACRO
+#else
 #define PR_FLOOR_LOG2(_log2,_n)   \
   PR_BEGIN_MACRO                    \
     PRUint32 j_ = (PRUint32)(_n);       \
     (_log2) = 0;                    \
     if ((j_) >> 16)                 \
         (_log2) += 16, (j_) >>= 16; \
     if ((j_) >> 8)                  \
         (_log2) += 8, (j_) >>= 8;   \
     if ((j_) >> 4)                  \
         (_log2) += 4, (j_) >>= 4;   \
     if ((j_) >> 2)                  \
         (_log2) += 2, (j_) >>= 2;   \
     if ((j_) >> 1)                  \
         (_log2) += 1;               \
   PR_END_MACRO
+#endif /* PR_HAVE_BUILTIN_BITSCAN32 */
 
 /*
 ** Macros for rotate left and right. The argument 'a' must be an unsigned
 ** 32-bit integer type such as PRUint32.
 **
 ** There is no rotate operation in the C Language, so the construct
 ** (a << 4) | (a >> 28) is frequently used instead. Most compilers convert
 ** this to a rotate instruction, but MSVC doesn't without a little help.
 ** To get MSVC to generate a rotate instruction, we have to use the _rotl
 ** or _rotr intrinsic and use a pragma to make it inline.
 **
 ** Note: MSVC in VS2005 will do an inline rotate instruction on the above
 ** construct.
 */
 
 #if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64) || \
     defined(_M_X64))
 #include <stdlib.h>
 #pragma intrinsic(_rotl, _rotr)
 #define PR_ROTATE_LEFT32(a, bits) _rotl(a, bits)
 #define PR_ROTATE_RIGHT32(a, bits) _rotr(a, bits)
 #else
 #define PR_ROTATE_LEFT32(a, bits) (((a) << (bits)) | ((a) >> (32 - (bits))))
 #define PR_ROTATE_RIGHT32(a, bits) (((a) >> (bits)) | ((a) << (32 - (bits))))
 #endif
 
 PR_END_EXTERN_C
 #endif /* prbit_h___ */