1/* 2 * Copyright (c) 2010 The WebM project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11#ifndef VP9_COMMON_VP9_SYSTEMDEPENDENT_H_ 12#define VP9_COMMON_VP9_SYSTEMDEPENDENT_H_ 13 14#ifdef _MSC_VER 15# include <math.h> // the ceil() definition must precede intrin.h 16# if _MSC_VER > 1310 && (defined(_M_X64) || defined(_M_IX86)) 17# include <intrin.h> 18# define USE_MSC_INTRIN 19# endif 20# define snprintf _snprintf 21#endif 22 23#ifdef __cplusplus 24extern "C" { 25#endif 26 27#include "./vpx_config.h" 28#if ARCH_X86 || ARCH_X86_64 29void vpx_reset_mmx_state(void); 30#define vp9_clear_system_state() vpx_reset_mmx_state() 31#else 32#define vp9_clear_system_state() 33#endif 34 35#if defined(_MSC_VER) && _MSC_VER < 1800 36// round is not defined in MSVC before VS2013. 37static INLINE int round(double x) { 38 if (x < 0) 39 return (int)ceil(x - 0.5); 40 else 41 return (int)floor(x + 0.5); 42} 43#endif 44 45// use GNU builtins where available. 46#if defined(__GNUC__) && \ 47 ((__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || __GNUC__ >= 4) 48static INLINE int get_msb(unsigned int n) { 49 return 31 ^ __builtin_clz(n); 50} 51#elif defined(USE_MSC_INTRIN) 52#pragma intrinsic(_BitScanReverse) 53 54static INLINE int get_msb(unsigned int n) { 55 unsigned long first_set_bit; 56 _BitScanReverse(&first_set_bit, n); 57 return first_set_bit; 58} 59#undef USE_MSC_INTRIN 60#else 61// Returns (int)floor(log2(n)). n must be > 0. 62static INLINE int get_msb(unsigned int n) { 63 int log = 0; 64 unsigned int value = n; 65 int i; 66 67 for (i = 4; i >= 0; --i) { 68 const int shift = (1 << i); 69 const unsigned int x = value >> shift; 70 if (x != 0) { 71 value = x; 72 log += shift; 73 } 74 } 75 return log; 76} 77#endif 78 79#ifdef __cplusplus 80} // extern "C" 81#endif 82 83#endif // VP9_COMMON_VP9_SYSTEMDEPENDENT_H_ 84