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Diffstat (limited to 'Modules/_decimal/libmpdec/bits.h')
| -rw-r--r-- | Modules/_decimal/libmpdec/bits.h | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/Modules/_decimal/libmpdec/bits.h b/Modules/_decimal/libmpdec/bits.h new file mode 100644 index 0000000..949ec94 --- /dev/null +++ b/Modules/_decimal/libmpdec/bits.h @@ -0,0 +1,192 @@ +/* + * Copyright (c) 2008-2012 Stefan Krah. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + + +#ifndef BITS_H +#define BITS_H + + +#include "mpdecimal.h" +#include <stdio.h> + + +/* Check if n is a power of 2. */ +static inline int +ispower2(mpd_size_t n) +{ + return n != 0 && (n & (n-1)) == 0; +} + +#if defined(ANSI) +/* + * Return the most significant bit position of n from 0 to 31 (63). + * Assumptions: n != 0. + */ +static inline int +mpd_bsr(mpd_size_t n) +{ + int pos = 0; + mpd_size_t tmp; + +#ifdef CONFIG_64 + tmp = n >> 32; + if (tmp != 0) { n = tmp; pos += 32; } +#endif + tmp = n >> 16; + if (tmp != 0) { n = tmp; pos += 16; } + tmp = n >> 8; + if (tmp != 0) { n = tmp; pos += 8; } + tmp = n >> 4; + if (tmp != 0) { n = tmp; pos += 4; } + tmp = n >> 2; + if (tmp != 0) { n = tmp; pos += 2; } + tmp = n >> 1; + if (tmp != 0) { n = tmp; pos += 1; } + + return pos + (int)n - 1; +} + +/* + * Return the least significant bit position of n from 0 to 31 (63). + * Assumptions: n != 0. + */ +static inline int +mpd_bsf(mpd_size_t n) +{ + int pos; + +#ifdef CONFIG_64 + pos = 63; + if (n & 0x00000000FFFFFFFFULL) { pos -= 32; } else { n >>= 32; } + if (n & 0x000000000000FFFFULL) { pos -= 16; } else { n >>= 16; } + if (n & 0x00000000000000FFULL) { pos -= 8; } else { n >>= 8; } + if (n & 0x000000000000000FULL) { pos -= 4; } else { n >>= 4; } + if (n & 0x0000000000000003ULL) { pos -= 2; } else { n >>= 2; } + if (n & 0x0000000000000001ULL) { pos -= 1; } +#else + pos = 31; + if (n & 0x000000000000FFFFUL) { pos -= 16; } else { n >>= 16; } + if (n & 0x00000000000000FFUL) { pos -= 8; } else { n >>= 8; } + if (n & 0x000000000000000FUL) { pos -= 4; } else { n >>= 4; } + if (n & 0x0000000000000003UL) { pos -= 2; } else { n >>= 2; } + if (n & 0x0000000000000001UL) { pos -= 1; } +#endif + return pos; +} +/* END ANSI */ + +#elif defined(ASM) +/* + * Bit scan reverse. Assumptions: a != 0. + */ +static inline int +mpd_bsr(mpd_size_t a) +{ + mpd_size_t retval; + + __asm__ ( +#ifdef CONFIG_64 + "bsrq %1, %0\n\t" +#else + "bsr %1, %0\n\t" +#endif + :"=r" (retval) + :"r" (a) + :"cc" + ); + + return (int)retval; +} + +/* + * Bit scan forward. Assumptions: a != 0. + */ +static inline int +mpd_bsf(mpd_size_t a) +{ + mpd_size_t retval; + + __asm__ ( +#ifdef CONFIG_64 + "bsfq %1, %0\n\t" +#else + "bsf %1, %0\n\t" +#endif + :"=r" (retval) + :"r" (a) + :"cc" + ); + + return (int)retval; +} +/* END ASM */ + +#elif defined(MASM) +#include <intrin.h> +/* + * Bit scan reverse. Assumptions: a != 0. + */ +static inline int __cdecl +mpd_bsr(mpd_size_t a) +{ + unsigned long retval; + +#ifdef CONFIG_64 + _BitScanReverse64(&retval, a); +#else + _BitScanReverse(&retval, a); +#endif + + return (int)retval; +} + +/* + * Bit scan forward. Assumptions: a != 0. + */ +static inline int __cdecl +mpd_bsf(mpd_size_t a) +{ + unsigned long retval; + +#ifdef CONFIG_64 + _BitScanForward64(&retval, a); +#else + _BitScanForward(&retval, a); +#endif + + return (int)retval; +} +/* END MASM (_MSC_VER) */ +#else + #error "missing preprocessor definitions" +#endif /* BSR/BSF */ + + +#endif /* BITS_H */ + + + |