| /* -*- 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 |
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| * 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___ */ |
