1 /* 2 * Copyright 2015 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 */ 23 24 #ifndef _ROUNDING_H 25 #define _ROUNDING_H 26 27 #include "c99_math.h" 28 29 #include <limits.h> 30 #include <stdint.h> 31 32 #if defined(__SSE__) || defined(_MSC_VER) 33 /* MSVC always has SSE nowadays */ 34 #include <xmmintrin.h> 35 #include <emmintrin.h> 36 #endif 37 38 #ifdef __SSE4_1__ 39 #include <smmintrin.h> 40 #endif 41 42 /* The C standard library has functions round()/rint()/nearbyint() that round 43 * their arguments according to the rounding mode set in the floating-point 44 * control register. While there are trunc()/ceil()/floor() functions that do 45 * a specific operation without modifying the rounding mode, there is no 46 * roundeven() in any version of C. 47 * 48 * Technical Specification 18661 (ISO/IEC TS 18661-1:2014) adds roundeven(), 49 * but it's unfortunately not implemented by glibc. 50 * 51 * This implementation differs in that it does not raise the inexact exception. 52 * 53 * We use rint() to implement these functions, with the assumption that the 54 * floating-point rounding mode has not been changed from the default Round 55 * to Nearest. 56 */ 57 58 /** 59 * \brief Rounds \c x to the nearest integer, with ties to the even integer. 60 */ 61 static inline float 62 _mesa_roundevenf(float x) 63 { 64 #ifdef __SSE4_1__ 65 float ret; 66 __m128 m = _mm_load_ss(&x); 67 m = _mm_round_ss(m, m, _MM_FROUND_CUR_DIRECTION | _MM_FROUND_NO_EXC); 68 _mm_store_ss(&ret, m); 69 return ret; 70 #else 71 return rintf(x); 72 #endif 73 } 74 75 /** 76 * \brief Rounds \c x to the nearest integer, with ties to the even integer. 77 */ 78 static inline double 79 _mesa_roundeven(double x) 80 { 81 #ifdef __SSE4_1__ 82 double ret; 83 __m128d m = _mm_load_sd(&x); 84 m = _mm_round_sd(m, m, _MM_FROUND_CUR_DIRECTION | _MM_FROUND_NO_EXC); 85 _mm_store_sd(&ret, m); 86 return ret; 87 #else 88 return rint(x); 89 #endif 90 } 91 92 /** 93 * \brief Rounds \c x to the nearest integer, with ties to the even integer, 94 * and returns the value as a long int. 95 */ 96 static inline long 97 _mesa_lroundevenf(float x) 98 { 99 #if defined(__SSE__) || defined(_MSC_VER) 100 #if LONG_MAX == INT64_MAX 101 return _mm_cvtss_si64(_mm_load_ss(&x)); 102 #elif LONG_MAX == INT32_MAX 103 return _mm_cvtss_si32(_mm_load_ss(&x)); 104 #else 105 #error "Unsupported long size" 106 #endif 107 #else 108 return lrintf(x); 109 #endif 110 } 111 112 /** 113 * \brief Rounds \c x to the nearest integer, with ties to the even integer, 114 * and returns the value as a long int. 115 */ 116 static inline long 117 _mesa_lroundeven(double x) 118 { 119 #if defined(__SSE__) || defined(_MSC_VER) 120 #if LONG_MAX == INT64_MAX 121 return _mm_cvtsd_si64(_mm_load_sd(&x)); 122 #elif LONG_MAX == INT32_MAX 123 return _mm_cvtsd_si32(_mm_load_sd(&x)); 124 #else 125 #error "Unsupported long size" 126 #endif 127 #else 128 return lrint(x); 129 #endif 130 } 131 132 #endif 133
