ref: d1c93aa5ef421077ac4516d14179b63ff05f1fbf
dir: /src/float_cast.h/
/* ** Copyright (C) 2001-2003 Erik de Castro Lopo <[email protected]> ** ** This program is free software; you can redistribute it and/or modify ** it under the terms of the GNU General Public License as published by ** the Free Software Foundation; either version 2 of the License, or ** (at your option) any later version. ** ** This program is distributed in the hope that it will be useful, ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ** GNU General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program; if not, write to the Free Software ** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. */ /* Version 1.3 */ /*============================================================================ ** On Intel Pentium processors (especially PIII and probably P4), converting ** from float to int is very slow. To meet the C specs, the code produced by ** most C compilers targeting Pentium needs to change the FPU rounding mode ** before the float to int conversion is performed. ** ** Changing the FPU rounding mode causes the FPU pipeline to be flushed. It ** is this flushing of the pipeline which is so slow. ** ** Fortunately the ISO C99 specifications define the functions lrint, lrintf, ** llrint and llrintf which fix this problem as a side effect. ** ** On Unix-like systems, the configure process should have detected the ** presence of these functions. If they weren't found we have to replace them ** here with a standard C cast. */ /* ** The C99 prototypes for lrint and lrintf are as follows: ** ** long int lrintf (float x) ; ** long int lrint (double x) ; */ #include "config.h" /* ** The presence of the required functions are detected during the configure ** process and the values HAVE_LRINT and HAVE_LRINTF are set accordingly in ** the config.h file. */ #define HAVE_LRINT_REPLACEMENT 0 #if (HAVE_LRINT && HAVE_LRINTF) /* ** These defines enable functionality introduced with the 1999 ISO C ** standard. They must be defined before the inclusion of math.h to ** engage them. If optimisation is enabled, these functions will be ** inlined. With optimisation switched off, you have to link in the ** maths library using -lm. */ #define _ISOC9X_SOURCE 1 #define _ISOC99_SOURCE 1 #define __USE_ISOC9X 1 #define __USE_ISOC99 1 #include <math.h> #elif (defined (WIN32) || defined (_WIN32)) #undef HAVE_LRINT_REPLACEMENT #define HAVE_LRINT_REPLACEMENT 1 #include <math.h> /* ** Win32 doesn't seem to have these functions. ** Therefore implement inline versions of these functions here. */ __inline long int lrint (double flt) { int intgr ; _asm { fld flt fistp intgr } ; return intgr ; } __inline long int lrintf (float flt) { int intgr ; _asm { fld flt fistp intgr } ; return intgr ; } #elif (defined (__MWERKS__) && defined (macintosh)) /* This MacOS 9 solution was provided by Stephane Letz */ #undef HAVE_LRINT_REPLACEMENT #define HAVE_LRINT_REPLACEMENT 1 #include <math.h> #undef lrint #undef lrintf #define lrint double2int #define lrintf float2int inline int float2int (register float in) { long res [2] ; asm { fctiw in, in stfd in, res } return res [1] ; } /* float2int */ inline int double2int (register double in) { long res [2] ; asm { fctiw in, in stfd in, res } return res [1] ; } /* double2int */ #elif (defined (__MACH__) && defined (__APPLE__)) /* For Apple MacOSX. */ #undef HAVE_LRINT_REPLACEMENT #define HAVE_LRINT_REPLACEMENT 1 #include <math.h> #undef lrint #undef lrintf #define lrint double2int #define lrintf float2int inline static long int float2int (register float in) { int res [2] ; __asm__ __volatile__ ( "fctiw %1, %1\n\t" "stfd %1, %0" : "=m" (res) /* Output */ : "f" (in) /* Input */ : "memory" ) ; return res [1] ; } /* lrintf */ inline static long int double2int (register double in) { int res [2] ; __asm__ __volatile__ ( "fctiw %1, %1\n\t" "stfd %1, %0" : "=m" (res) /* Output */ : "f" (in) /* Input */ : "memory" ) ; return res [1] ; } /* lrint */ #else #ifndef __sgi #warning "Don't have the functions lrint() and lrintf()." #warning "Replacing these functions with a standard C cast." #endif #include <math.h> #define lrint(dbl) ((long) (dbl)) #define lrintf(flt) ((long) (flt)) #endif /* ** Do not edit or modify anything in this comment block. ** The arch-tag line is a file identity tag for the GNU Arch ** revision control system. ** ** arch-tag: 25418b9e-cfe8-4145-a3b3-a92388dd37c5 */