diff options
Diffstat (limited to 'libavutil/intmath.h')
| -rw-r--r-- | libavutil/intmath.h | 109 |
1 files changed, 64 insertions, 45 deletions
diff --git a/libavutil/intmath.h b/libavutil/intmath.h index a5ee6525ee..9573109e9d 100644 --- a/libavutil/intmath.h +++ b/libavutil/intmath.h @@ -1,20 +1,20 @@ /* * Copyright (c) 2010 Mans Rullgard <mans@mansr.com> * - * This file is part of Libav. + * This file is part of FFmpeg. * - * Libav is free software; you can redistribute it and/or + * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * - * Libav is distributed in the hope that it will be useful, + * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public - * License along with Libav; if not, write to the Free Software + * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ @@ -29,22 +29,20 @@ #if ARCH_ARM # include "arm/intmath.h" #endif +#if ARCH_X86 +# include "x86/intmath.h" +#endif -/** - * @addtogroup lavu_internal - * @{ - */ - -#if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4) - +#if HAVE_FAST_CLZ +#if AV_GCC_VERSION_AT_LEAST(3,4) #ifndef ff_log2 # define ff_log2(x) (31 - __builtin_clz((x)|1)) # ifndef ff_log2_16bit # define ff_log2_16bit av_log2 # endif #endif /* ff_log2 */ - #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ +#endif extern const uint8_t ff_log2_tab[256]; @@ -86,59 +84,80 @@ static av_always_inline av_const int ff_log2_16bit_c(unsigned int v) #define av_log2_16bit ff_log2_16bit /** - * @} - */ - -/** * @addtogroup lavu_math * @{ */ -#if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4) +#if HAVE_FAST_CLZ +#if AV_GCC_VERSION_AT_LEAST(3,4) #ifndef ff_ctz #define ff_ctz(v) __builtin_ctz(v) #endif +#ifndef ff_ctzll +#define ff_ctzll(v) __builtin_ctzll(v) +#endif +#ifndef ff_clz +#define ff_clz(v) __builtin_clz(v) +#endif +#endif #endif #ifndef ff_ctz #define ff_ctz ff_ctz_c +/** + * Trailing zero bit count. + * + * @param v input value. If v is 0, the result is undefined. + * @return the number of trailing 0-bits + */ +/* We use the De-Bruijn method outlined in: + * http://supertech.csail.mit.edu/papers/debruijn.pdf. */ static av_always_inline av_const int ff_ctz_c(int v) { - int c; + static const uint8_t debruijn_ctz32[32] = { + 0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8, + 31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9 + }; + return debruijn_ctz32[(uint32_t)((v & -v) * 0x077CB531U) >> 27]; +} +#endif - if (v & 0x1) - return 0; +#ifndef ff_ctzll +#define ff_ctzll ff_ctzll_c +/* We use the De-Bruijn method outlined in: + * http://supertech.csail.mit.edu/papers/debruijn.pdf. */ +static av_always_inline av_const int ff_ctzll_c(long long v) +{ + static const uint8_t debruijn_ctz64[64] = { + 0, 1, 2, 53, 3, 7, 54, 27, 4, 38, 41, 8, 34, 55, 48, 28, + 62, 5, 39, 46, 44, 42, 22, 9, 24, 35, 59, 56, 49, 18, 29, 11, + 63, 52, 6, 26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10, + 51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12 + }; + return debruijn_ctz64[(uint64_t)((v & -v) * 0x022FDD63CC95386DU) >> 58]; +} +#endif - c = 1; - if (!(v & 0xffff)) { - v >>= 16; - c += 16; - } - if (!(v & 0xff)) { - v >>= 8; - c += 8; - } - if (!(v & 0xf)) { - v >>= 4; - c += 4; - } - if (!(v & 0x3)) { - v >>= 2; - c += 2; +#ifndef ff_clz +#define ff_clz ff_clz_c +static av_always_inline av_const unsigned ff_clz_c(unsigned x) +{ + unsigned i = sizeof(x) * 8; + + while (x) { + x >>= 1; + i--; } - c -= v & 0x1; - return c; + return i; } #endif -/** - * Trailing zero bit count. - * - * @param v input value. If v is 0, the result is undefined. - * @return the number of trailing 0-bits - */ -int av_ctz(int v); +#if AV_GCC_VERSION_AT_LEAST(3,4) +#ifndef av_parity +#define av_parity __builtin_parity +#endif +#endif /** * @} |