1/* 2 * Copyright (c) 2010 Mans Rullgard <mans@mansr.com> 3 * 4 * This file is part of Libav. 5 * 6 * Libav 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 * Libav 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 Libav; 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_INTMATH_H 22#define AVUTIL_INTMATH_H 23 24#include <stdint.h> 25#include "config.h" 26#include "attributes.h" 27 28/** 29 * @addtogroup lavu_internal 30 * @{ 31 */ 32 33extern const uint32_t ff_inverse[257]; 34 35#if ARCH_ARM 36# include "arm/intmath.h" 37#elif ARCH_X86 38# include "x86/intmath.h" 39#endif 40 41#if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4) 42 43#ifndef av_log2 44# define av_log2(x) (31 - __builtin_clz((x)|1)) 45# ifndef av_log2_16bit 46# define av_log2_16bit av_log2 47# endif 48#endif /* av_log2 */ 49 50#endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ 51 52#ifndef FASTDIV 53# if CONFIG_FASTDIV 54# define FASTDIV(a,b) ((uint32_t)((((uint64_t)a) * ff_inverse[b]) >> 32)) 55# else 56# define FASTDIV(a,b) ((a) / (b)) 57# endif 58#endif /* FASTDIV */ 59 60#include "common.h" 61 62extern const uint8_t ff_sqrt_tab[256]; 63 64static inline av_const unsigned int ff_sqrt(unsigned int a) 65{ 66 unsigned int b; 67 68 if (a < 255) return (ff_sqrt_tab[a + 1] - 1) >> 4; 69 else if (a < (1 << 12)) b = ff_sqrt_tab[a >> 4] >> 2; 70#if !CONFIG_SMALL 71 else if (a < (1 << 14)) b = ff_sqrt_tab[a >> 6] >> 1; 72 else if (a < (1 << 16)) b = ff_sqrt_tab[a >> 8] ; 73#endif 74 else { 75 int s = av_log2_16bit(a >> 16) >> 1; 76 unsigned int c = a >> (s + 2); 77 b = ff_sqrt_tab[c >> (s + 8)]; 78 b = FASTDIV(c,b) + (b << s); 79 } 80 81 return b - (a < b * b); 82} 83 84/** 85 * @} 86 */ 87#endif /* AVUTIL_INTMATH_H */ 88