ref: 9a9fa10c760b59e48c567d408de3878498755f84
dir: /common/libsndfile/src/float_cast.h/
/*
** Copyright (C) 2001-2002 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 Lesser General Public License as published by
** the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
**
** You should have received a copy of the GNU Lesser 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.
*/
#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))
#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 (__APPLE__))
/* This MacOS 9 solution was provided by Stephane Letz */
#include <math.h>
#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. */
#include <math.h>
inline static long int
lrintf (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
lrint (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
#warning "Don't have the functions lrint() and lrintf()."
#warning "Replacing these functions with a standard C cast."
#include <math.h>
#define lrint(dbl) ((int) (dbl))
#define lrintf(flt) ((int) (flt))
#endif