| /* |
| * 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 */ |
| |
| |
| |