110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
|
/*
|
||
|
|
** Copyright (C) 2001 Erik de Castro Lopo <erikd AT mega-nerd DOT com>
|
||
|
|
**
|
||
|
|
** Permission to use, copy, modify, distribute, and sell this file for any
|
||
|
|
** purpose is hereby granted without fee, provided that the above copyright
|
||
|
|
** and this permission notice appear in all copies. No representations are
|
||
|
|
** made about the suitability of this software for any purpose. It is
|
||
|
|
** provided "as is" without express or implied warranty.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* Version 1.1 */
|
||
|
|
|
||
|
|
#ifndef FLOAT_CAST_H
|
||
|
|
#define FLOAT_CAST_H
|
||
|
|
|
||
|
|
/*============================================================================
|
||
|
|
** 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) ;
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* 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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#if (HAVE_LRINTF)
|
||
|
|
/*#if 0*/
|
||
|
|
|
||
|
|
/* 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>
|
||
|
|
#define float2int(x) lrintf(x)
|
||
|
|
|
||
|
|
#elif (defined(HAVE_LRINT))
|
||
|
|
|
||
|
|
#define _ISOC9X_SOURCE 1
|
||
|
|
#define _ISOC99_SOURCE 1
|
||
|
|
|
||
|
|
#define __USE_ISOC9X 1
|
||
|
|
#define __USE_ISOC99 1
|
||
|
|
|
||
|
|
#include <math.h>
|
||
|
|
#define float2int(x) lrint(x)
|
||
|
|
|
||
|
|
#elif (defined (WIN32) || defined (_WIN32))
|
||
|
|
|
||
|
|
#include <math.h>
|
||
|
|
|
||
|
|
/* Win32 doesn't seem to have these functions.
|
||
|
|
** Therefore implement inline versions of these functions here.
|
||
|
|
*/
|
||
|
|
|
||
|
|
__inline long int
|
||
|
|
float2int (float flt)
|
||
|
|
{ int intgr;
|
||
|
|
|
||
|
|
_asm
|
||
|
|
{ fld flt
|
||
|
|
fistp intgr
|
||
|
|
} ;
|
||
|
|
|
||
|
|
return intgr ;
|
||
|
|
}
|
||
|
|
|
||
|
|
#else
|
||
|
|
|
||
|
|
#ifdef __GNUC__ /* supported by gcc, but not by all other compilers*/
|
||
|
|
#warning "Don't have the functions lrint() and lrintf ()."
|
||
|
|
#warning "Replacing these functions with a standard C cast."
|
||
|
|
#endif /* __GNUC__ */
|
||
|
|
|
||
|
|
#include <math.h>
|
||
|
|
|
||
|
|
#define float2int(flt) ((int)(floor(.5+flt)))
|
||
|
|
|
||
|
|
#endif
|
||
|
|
|
||
|
|
|
||
|
|
#endif /* FLOAT_CAST_H */
|