diff options
Diffstat (limited to 'pr/include/prbit.h')
| -rw-r--r-- | pr/include/prbit.h | 81 |
1 files changed, 46 insertions, 35 deletions
diff --git a/pr/include/prbit.h b/pr/include/prbit.h index 1f4fc843..f0a51d01 100644 --- a/pr/include/prbit.h +++ b/pr/include/prbit.h @@ -1,39 +1,7 @@ /* -*- 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, - * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License - * for the specific language governing rights and limitations under the - * License. - * - * The Original Code is the Netscape Portable Runtime (NSPR). - * - * The Initial Developer of the Original Code is - * Netscape Communications Corporation. - * Portions created by the Initial Developer are Copyright (C) 1998-2000 - * the Initial Developer. All Rights Reserved. - * - * Contributor(s): - * - * Alternatively, the contents of this file may be used under the terms of - * either the GNU General Public License Version 2 or later (the "GPL"), or - * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), - * in which case the provisions of the GPL or the LGPL are applicable instead - * of those above. If you wish to allow use of your version of this file only - * under the terms of either the GPL or the LGPL, and not to allow others to - * use your version of this file under the terms of the MPL, indicate your - * decision by deleting the provisions above and replace them with the notice - * and other provisions required by the GPL or the LGPL. If you do not delete - * the provisions above, a recipient may use your version of this file under - * the terms of any one of the MPL, the GPL or the LGPL. - * - * ***** END LICENSE BLOCK ***** */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #ifndef prbit_h___ #define prbit_h___ @@ -41,6 +9,33 @@ #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 */ @@ -67,6 +62,13 @@ 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); \ @@ -84,6 +86,7 @@ NSPR_API(PRIntn) PR_FloorLog2(PRUint32 i); 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 @@ -91,6 +94,13 @@ NSPR_API(PRIntn) PR_FloorLog2(PRUint32 i); ** ** 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); \ @@ -106,6 +116,7 @@ NSPR_API(PRIntn) PR_FloorLog2(PRUint32 i); 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 |