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