libavutil/x86/intmath.h

   1 /*
   2  * Copyright (c) 2015 James Almer
   3  *
   4  * This file is part of FFmpeg.
   5  *
   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.
  10  *
  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.
  15  *
  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
  19  */
  20
  21 #ifndef AVUTIL_X86_INTMATH_H
  22 #define AVUTIL_X86_INTMATH_H
  23
  24 #include <stdint.h>
  25 #include <stdlib.h>
  26 #if HAVE_FAST_CLZ
  27 #if defined(_MSC_VER)
  28 #include <intrin.h>
  29 #elif defined(__INTEL_COMPILER)
  30 #include <immintrin.h>
  31 #endif
  32 #endif
  33 #include "config.h"
  34
  35 #if HAVE_FAST_CLZ
  36 #if (defined(__INTEL_COMPILER) && (__INTEL_COMPILER>=1216)) || defined(_MSC_VER)
  37 #   if defined(__INTEL_COMPILER)
  38 #       define ff_log2(x) (_bit_scan_reverse((x)|1))
  39 #   else
  40 #       define ff_log2 ff_log2_x86
  41 static av_always_inline av_const int ff_log2_x86(unsigned int v)
  42 {
  43     unsigned long n;
  44     _BitScanReverse(&n, v|1);
  45     return n;
  46 }
  47 #   endif
  48 #   define ff_log2_16bit av_log2
  49
  50 #if defined(__INTEL_COMPILER) || (defined(_MSC_VER) && (_MSC_VER >= 1700) && \
  51                                   (defined(__BMI__) || !defined(__clang__)))
  52 #   define ff_ctz(v) _tzcnt_u32(v)
  53
  54 #   if ARCH_X86_64
  55 #       define ff_ctzll(v) _tzcnt_u64(v)
  56 #   else
  57 #       define ff_ctzll ff_ctzll_x86
  58 static av_always_inline av_const int ff_ctzll_x86(long long v)
  59 {
  60     return ((uint32_t)v == 0) ? _tzcnt_u32((uint32_t)(v >> 32)) + 32 : _tzcnt_u32((uint32_t)v);
  61 }
  62 #   endif
  63 #endif /* _MSC_VER */
  64
  65 #endif /* __INTEL_COMPILER */
  66
  67 #endif /* HAVE_FAST_CLZ */
  68
  69 #if defined(__GNUC__) || defined(__clang__)
  70
  71 /* Our generic version of av_popcount is faster than GCC's built-in on
  72  * CPUs that don't support the popcnt instruction.
  73  */
  74 #if defined(__POPCNT__)
  75     #define av_popcount   __builtin_popcount
  76 #if ARCH_X86_64
  77     #define av_popcount64 __builtin_popcountll
  78 #endif
  79
  80 #endif /* __POPCNT__ */
  81
  82 #if defined(__BMI2__)
  83
  84 #if AV_GCC_VERSION_AT_LEAST(5,1) || AV_HAS_BUILTIN(__builtin_ia32_bzhi_si)
  85 #if defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
  86 #define av_zero_extend av_zero_extend_bmi2
  87 static av_always_inline av_const unsigned av_zero_extend_bmi2(unsigned a, unsigned p)
  88 {
  89     if (p > 31) abort();
  90     return __builtin_ia32_bzhi_si(a, p);
  91 }
  92 #else
  93 #define av_zero_extend __builtin_ia32_bzhi_si
  94 #endif
  95 #elif HAVE_INLINE_ASM
  96 /* GCC releases before 5.1.0 have a broken bzhi builtin, so for those we
  97  * implement it using inline assembly
  98  */
  99 #define av_zero_extend av_zero_extend_bmi2
 100 static av_always_inline av_const unsigned av_zero_extend_bmi2(unsigned a, unsigned p)
 101 {
 102 #if defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
 103     if (p > 31) abort();
 104 #endif
 105     if (av_builtin_constant_p(p))
 106         return a & ((1U << p) - 1);
 107     else {
 108         unsigned x;
 109         __asm__ ("bzhi %2, %1, %0 \n\t" : "=r"(x) : "rm"(a), "r"(p));
 110         return x;
 111     }
 112 }
 113 #endif /* AV_GCC_VERSION_AT_LEAST */
 114
 115 #endif /* __BMI2__ */
 116
 117 #endif /* __GNUC__ */
 118
 119 #endif /* AVUTIL_X86_INTMATH_H */