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 24 extern "C" { 25 #endif 26 27 #include "./vpx_config.h" 28 #if ARCH_X86_32 || ARCH_X86_64 29 void 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. round(double x)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) get_msb(unsigned int n)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 get_msb(unsigned int n)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. get_msb(unsigned int n)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