| /* |
| * Copyright (c) 2010 Mans Rullgard <mans@mansr.com> |
| * |
| * This file is part of FFmpeg. |
| * |
| * 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. |
| * |
| * 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 FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #ifndef AVUTIL_INTMATH_H |
| #define AVUTIL_INTMATH_H |
| |
| #include <stdint.h> |
| #include "config.h" |
| #include "attributes.h" |
| |
| /** |
| * @addtogroup lavu_internal |
| * @{ |
| */ |
| |
| extern const uint32_t ff_inverse[257]; |
| |
| #if ARCH_ARM |
| # include "arm/intmath.h" |
| #elif ARCH_X86 |
| # include "x86/intmath.h" |
| #endif |
| |
| #if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4) |
| |
| #ifndef av_log2 |
| # define av_log2(x) (31 - __builtin_clz((x)|1)) |
| # ifndef av_log2_16bit |
| # define av_log2_16bit av_log2 |
| # endif |
| #endif /* av_log2 */ |
| |
| #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ |
| |
| #ifndef FASTDIV |
| # if CONFIG_FASTDIV |
| # define FASTDIV(a,b) ((uint32_t)((((uint64_t)a) * ff_inverse[b]) >> 32)) |
| # else |
| # define FASTDIV(a,b) ((a) / (b)) |
| # endif |
| #endif /* FASTDIV */ |
| |
| #include "common.h" |
| |
| extern const uint8_t ff_sqrt_tab[256]; |
| |
| static inline av_const unsigned int ff_sqrt(unsigned int a) |
| { |
| unsigned int b; |
| |
| if (a < 255) return (ff_sqrt_tab[a + 1] - 1) >> 4; |
| else if (a < (1 << 12)) b = ff_sqrt_tab[a >> 4] >> 2; |
| #if !CONFIG_SMALL |
| else if (a < (1 << 14)) b = ff_sqrt_tab[a >> 6] >> 1; |
| else if (a < (1 << 16)) b = ff_sqrt_tab[a >> 8] ; |
| #endif |
| else { |
| int s = av_log2_16bit(a >> 16) >> 1; |
| unsigned int c = a >> (s + 2); |
| b = ff_sqrt_tab[c >> (s + 8)]; |
| b = FASTDIV(c,b) + (b << s); |
| } |
| |
| return b - (a < b * b); |
| } |
| |
| /** |
| * @} |
| */ |
| #endif /* AVUTIL_INTMATH_H */ |