Source code of Windows XP (NT5)
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2.5 KiB

/***
*fpinit.c - Initialize floating point
*
* Copyright (c) 1991-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
*
*Revision History:
* 09-29-91 GDP merged fpmath.c and fltused.asm to produce this file
* 09-30-91 GDP per thread initialization and termination hooks
* 03-04-92 GDP removed finit instruction
* 11-06-92 GDP added __fastflag for FORTRAN libs
* 03-23-93 JWM added _setdefaultprecision() to _fpmath()
* 12-09-94 JWM added __adjust_fdiv for Pentium FDIV detection
* 12-12-94 SKS _adjust_fdiv must be exported in MSVCRT.LIB model
* 02-06-95 JWM Mac merge
* 04-04-95 JWM Clear exceptions after FDIV detection (x86 only).
* 11-15-95 BWT Assume P5 FDIV problem will be handled in the OS.
* 10-07-97 RDL Added IA64.
*
*******************************************************************************/
#include <cv.h>
#ifdef _M_IX86
#include <testfdiv.h>
#endif
#if defined(_AMD64_) || defined(_M_IA64)
#include <trans.h>
#endif
int _fltused = 0x9875;
int _ldused = 0x9873;
int __fastflag = 0;
void _cfltcvt_init(void);
void _fpmath(void);
void _fpclear(void);
#if defined(_M_AMD64) || defined(_M_IX86) || defined(_M_IA64)
#ifndef _CRTIMP
#ifdef CRTDLL
#define _CRTIMP __declspec(dllexport)
#else
#define _CRTIMP
#endif
#endif
_CRTIMP int _adjust_fdiv = 0;
extern void _setdefaultprecision();
#endif
void (* _FPinit)(void) = _fpmath;
void (* _FPmtinit)(void) = _fpclear;
void (* _FPmtterm)(void) = _fpclear;
void _fpmath()
{
//
// There is no need for 'finit'
// since this is done by the OS
//
_cfltcvt_init();
#ifdef _M_IX86
#ifndef NT_BUILD
_adjust_fdiv = _ms_p5_mp_test_fdiv();
#endif
_setdefaultprecision();
_asm {
fnclex
}
#elif defined(_M_IA64)
/* _setdefaultprecision(); */
_clrfp();
#endif
return;
}
void _fpclear()
{
//
// There is no need for 'finit'
// since this is done by the OS
//
return;
}
void _cfltcvt_init()
{
_cfltcvt_tab[0] = (PFV) _cfltcvt;
_cfltcvt_tab[1] = (PFV) _cropzeros;
_cfltcvt_tab[2] = (PFV) _fassign;
_cfltcvt_tab[3] = (PFV) _forcdecpt;
_cfltcvt_tab[4] = (PFV) _positive;
/* map long double to double */
_cfltcvt_tab[5] = (PFV) _cfltcvt;
}
/*
* Routine to set the fast flag in order to speed up computation
* of transcendentals at the expense of limiting error checking
*/
int __setfflag(int new)
{
int old = __fastflag;
__fastflag = new;
return old;
}