2 * Copyright (c) 2015 James Almer
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 #ifndef AVUTIL_X86_INTMATH_H
22 #define AVUTIL_X86_INTMATH_H
28 #if defined(__INTEL_COMPILER)
29 # define ff_log2(x) (_bit_scan_reverse((x)|1))
30 # define ff_log2_16bit av_log2
32 # define ff_ctz(v) _bit_scan_forward(v)
34 # define ff_ctzll ff_ctzll_x86
35 static av_always_inline av_const int ff_ctzll_x86(long long v)
39 __asm__("bsfq %1,%0" : "=r" (c) : "r" (v));
42 return ((uint32_t)v == 0) ? _bit_scan_forward((uint32_t)(v >> 32)) + 32 : _bit_scan_forward((uint32_t)v);
45 #elif defined(_MSC_VER)
46 # define ff_log2 ff_log2_x86
47 static av_always_inline av_const int ff_log2_x86(unsigned int v) {
49 _BitScanReverse(&n, v | 1);
52 # define ff_log2_16bit av_log2
54 # define ff_ctz ff_ctz_x86
55 static av_always_inline av_const int ff_ctz_x86(int v) {
57 _BitScanForward(&c, v);
61 # define ff_ctzll ff_ctzll_x86
62 static av_always_inline av_const int ff_ctzll_x86(long long v)
66 _BitScanForward64(&c, v);
68 if ((uint32_t)v == 0) {
69 _BitScanForward(&c, (uint32_t)(v >> 32));
72 _BitScanForward(&c, (uint32_t)v);
78 #endif /* __INTEL_COMPILER */
80 #endif /* HAVE_FAST_CLZ */
84 /* Our generic version of av_popcount is faster than GCC's built-in on
85 * CPUs that don't support the popcnt instruction.
87 #if defined(__POPCNT__)
88 #define av_popcount __builtin_popcount
90 #define av_popcount64 __builtin_popcountll
93 #endif /* __POPCNT__ */
97 #if AV_GCC_VERSION_AT_LEAST(5,1)
98 #define av_mod_uintp2 __builtin_ia32_bzhi_si
100 /* GCC releases before 5.1.0 have a broken bzhi builtin, so for those we
101 * implement it using inline assembly
103 #define av_mod_uintp2 av_mod_uintp2_bmi2
104 static av_always_inline av_const unsigned av_mod_uintp2_bmi2(unsigned a, unsigned p)
106 if (av_builtin_constant_p(p))
107 return a & ((1 << p) - 1);
110 __asm__ ("bzhi %2, %1, %0 \n\t" : "=r"(x) : "rm"(a), "r"(p));
114 #endif /* AV_GCC_VERSION_AT_LEAST */
116 #endif /* __BMI2__ */
118 #endif /* __GNUC__ */
120 #endif /* AVUTIL_X86_INTMATH_H */