kolibrios/programs/develop/open watcom/trunk/clib/fpu/cntrl87.c

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/****************************************************************************
*
* Open Watcom Project
*
* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
* ========================================================================
*
* This file contains Original Code and/or Modifications of Original
* Code as defined in and that are subject to the Sybase Open Watcom
* Public License version 1.0 (the 'License'). You may not use this file
* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
* provided with the Original Code and Modifications, and is also
* available at www.sybase.com/developer/opensource.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
* NON-INFRINGEMENT. Please see the License for the specific language
* governing rights and limitations under the License.
*
* ========================================================================
*
* Description: WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
* DESCRIBE IT HERE!
*
****************************************************************************/
#include "variety.h"
#include <math.h>
#include <float.h>
#include "rtdata.h"
extern void __fstcw();
extern void __fldcw();
#if defined(__WINDOWS__) && !defined(__WINDOWS_386__)
extern void __far _fpmath();
#pragma aux _fpmath "__fpmath";
void __win87em_fldcw(unsigned int);
#pragma aux __win87em_fldcw = \
"push bx" \
"mov bx, 4h" \
"call far ptr _fpmath" \
"pop bx" \
parm [ax]
unsigned int __win87em_fstcw(void);
#pragma aux __win87em_fstcw = \
"push bx" \
"mov bx, 5h" \
"call far ptr _fpmath" \
"pop bx" \
value [ax]
#elif defined( __DOS_086__ )
extern unsigned char __dos87real;
#pragma aux __dos87real "*";
extern unsigned short __dos87emucall;
#pragma aux __dos87emucall "*";
void _WCI86NEAR __dos_emu_fldcw( unsigned short * );
#pragma aux __dos_emu_fldcw "*" = \
"mov ax,3" \
"call __dos87emucall" \
parm [bx];
void _WCI86NEAR __dos_emu_fstcw( unsigned short * );
#pragma aux __dos_emu_fstcw "*" = \
"mov ax,4" \
"call __dos87emucall" \
parm [bx];
#endif
#if defined(__386__)
#pragma aux __fstcw = \
"fstcw ss:[edi]" \
"fwait" \
parm caller [edi];
#pragma aux __fldcw = \
"fldcw ss:[edi]" \
parm caller [edi];
#else
#pragma aux __fstcw = \
"xchg ax,bp" \
"fstcw [bp]" \
"fwait" \
"xchg ax,bp" \
parm caller [ax];
#pragma aux __fldcw = \
"xchg ax,bp" \
"fldcw [bp]" \
"xchg ax,bp" \
parm caller [ax];
#endif
_WCRTLINK unsigned _control87( unsigned new, unsigned mask )
/**********************************************************/
{
auto short unsigned int control_word;
control_word = 0;
if( _RWD_8087 ) {
#if defined(__WINDOWS__) && !defined(__WINDOWS_386__)
__fstcw( &control_word );
control_word = __win87em_fstcw();
if( mask != 0 ) {
control_word = (control_word & ~mask) | (new & mask);
__fldcw( &control_word );
__fstcw( &control_word ); /* 17-sep-91 */
__win87em_fldcw(control_word);
}
#elif defined( __DOS_086__ )
if( __dos87real ) {
__fstcw( &control_word );
if( mask != 0 ) {
control_word = (control_word & ~mask) | (new & mask);
__fldcw( &control_word );
__fstcw( &control_word );
}
}
if( __dos87emucall ) {
__dos_emu_fstcw( &control_word );
if( mask != 0 ) {
control_word = (control_word & ~mask) | (new & mask);
__dos_emu_fldcw( &control_word );
__dos_emu_fstcw( &control_word );
}
}
#else
__fstcw( &control_word );
if( mask != 0 ) {
control_word = (control_word & ~mask) | (new & mask);
__fldcw( &control_word );
__fstcw( &control_word ); /* 17-sep-91 */
}
#endif
}
return( control_word );
}