1 /* Copyright (C) 2001 Erik de Castro Lopo <erikd AT mega-nerd DOT com> */ 2 /* 3 Redistribution and use in source and binary forms, with or without 4 modification, are permitted provided that the following conditions 5 are met: 6 7 - Redistributions of source code must retain the above copyright 8 notice, this list of conditions and the following disclaimer. 9 10 - Redistributions in binary form must reproduce the above copyright 11 notice, this list of conditions and the following disclaimer in the 12 documentation and/or other materials provided with the distribution. 13 14 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 15 ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 16 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 17 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR 18 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 19 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 20 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 21 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 22 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 23 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 24 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 /* Version 1.1 */ 28 29 #ifndef FLOAT_CAST_H 30 #define FLOAT_CAST_H 31 32 /*============================================================================ 33 ** On Intel Pentium processors (especially PIII and probably P4), converting 34 ** from float to int is very slow. To meet the C specs, the code produced by 35 ** most C compilers targeting Pentium needs to change the FPU rounding mode 36 ** before the float to int conversion is performed. 37 ** 38 ** Changing the FPU rounding mode causes the FPU pipeline to be flushed. It 39 ** is this flushing of the pipeline which is so slow. 40 ** 41 ** Fortunately the ISO C99 specifications define the functions lrint, lrintf, 42 ** llrint and llrintf which fix this problem as a side effect. 43 ** 44 ** On Unix-like systems, the configure process should have detected the 45 ** presence of these functions. If they weren't found we have to replace them 46 ** here with a standard C cast. 47 */ 48 49 /* 50 ** The C99 prototypes for lrint and lrintf are as follows: 51 ** 52 ** long int lrintf (float x) ; 53 ** long int lrint (double x) ; 54 */ 55 56 /* The presence of the required functions are detected during the configure 57 ** process and the values HAVE_LRINT and HAVE_LRINTF are set accordingly in 58 ** the config.h file. 59 */ 60 61 #if (HAVE_LRINTF) 62 /*#if 0*/ 63 64 /* These defines enable functionality introduced with the 1999 ISO C 65 ** standard. They must be defined before the inclusion of math.h to 66 ** engage them. If optimisation is enabled, these functions will be 67 ** inlined. With optimisation switched off, you have to link in the 68 ** maths library using -lm. 69 */ 70 71 #define _ISOC9X_SOURCE 1 72 #define _ISOC99_SOURCE 1 73 74 #define __USE_ISOC9X 1 75 #define __USE_ISOC99 1 76 77 #include <math.h> 78 #define float2int(x) lrintf(x) 79 80 #elif (defined(HAVE_LRINT)) 81 82 #define _ISOC9X_SOURCE 1 83 #define _ISOC99_SOURCE 1 84 85 #define __USE_ISOC9X 1 86 #define __USE_ISOC99 1 87 88 #include <math.h> 89 #define float2int(x) lrint(x) 90 91 #elif (defined (WIN64) || defined (_WIN64)) 92 #include <xmmintrin.h> 93 float2int(float value)94 __inline long int float2int(float value) 95 { 96 return _mm_cvtss_si32(_mm_load_ss(&value)); 97 } 98 #elif (defined (WIN32) || defined (_WIN32)) 99 100 #include <math.h> 101 102 /* Win32 doesn't seem to have these functions. 103 ** Therefore implement inline versions of these functions here. 104 */ 105 106 __inline long int float2int(float flt)107 float2int (float flt) 108 { int intgr; 109 110 _asm 111 { fld flt 112 fistp intgr 113 } ; 114 115 return intgr ; 116 } 117 118 #else 119 120 #ifdef __GNUC__ /* supported by gcc, but not by all other compilers*/ 121 #warning "Don't have the functions lrint() and lrintf ()." 122 #warning "Replacing these functions with a standard C cast." 123 #endif /* __GNUC__ */ 124 125 #include <math.h> 126 127 #define float2int(flt) ((int)(floor(.5+flt))) 128 129 #endif 130 131 132 #endif /* FLOAT_CAST_H */ 133