/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* 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___ #include "prtypes.h" PR_BEGIN_EXTERN_C /* ** Replace compare/jump/add/shift sequence with compiler built-in/intrinsic ** functions. */ #if defined(_WIN32) && (_MSC_VER >= 1300) && \ (defined(_M_IX86) || defined(_M_AMD64) || defined(_M_ARM)) # include <intrin.h> # 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) || defined(_M_ARM)) #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___ */