freebsd-dev/sys/amd64/include/floatingpoint.h
Bruce Evans 136956ed12 Fixed the return value of fpsetmask(). The API requires inversion of the
mask on both input and output to fpsetmask(), but this was only done for
input, so fpsetmask() returned the complement of the old mask (ANDed with
the mask bitfield).

PR:		38170
MFC after:	4 weeks
2002-06-01 17:39:46 +00:00

131 lines
4.2 KiB
C

/*-
* Copyright (c) 1993 Andrew Moore, Talke Studio
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#) floatingpoint.h 1.0 (Berkeley) 9/23/93
* $FreeBSD$
*/
#ifndef _FLOATINGPOINT_H_
#define _FLOATINGPOINT_H_
/*
* IEEE floating point structure and function definitions
*/
/*-
* XXX the following undocumented pollution is exported:
* fpsetsticky().
* FP*FLD, FP*OFF and FP*REG from <machine/ieeefp.h>
*/
#include <sys/cdefs.h>
#include <machine/ieeefp.h>
#ifdef __GNUC__
#define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr)))
#define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr)))
#define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr)))
#define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr)))
/*
* return the contents of a FP register
*/
static __inline__ int
__fpgetreg(int _reg)
{
unsigned short _mem;
/*-
* This is more efficient than it looks. The switch gets optimized
* away if _reg is constant.
*
* The default case only supports _reg == 0. We could handle more
* registers (e.g., tags) using fnstenv, but the interface doesn't
* support more.
*/
switch(_reg) {
default:
__fnstcw(&_mem);
break;
case FP_STKY_REG:
__fnstsw(&_mem);
break;
}
return _mem;
}
/*
* set a FP mode; return previous mode
*/
static __inline__ int
__fpsetreg(int _m, int _reg, int _fld, int _off)
{
unsigned _env[7];
unsigned _p;
/*
* _reg == 0 could be handled better using fnstcw/fldcw.
*/
__fnstenv(_env);
_p = (_env[_reg] & _fld) >> _off;
_env[_reg] = (_env[_reg] & ~_fld) | (_m << _off & _fld);
__fldenv(_env);
return _p;
}
#endif /* __GNUC__ */
/*
* SysV/386 FP control interface
*/
#define fpgetround() ((fp_rnd_t) \
((__fpgetreg(FP_RND_REG) & FP_RND_FLD) >> FP_RND_OFF))
#define fpsetround(m) ((fp_rnd_t) \
__fpsetreg((m), FP_RND_REG, FP_RND_FLD, FP_RND_OFF))
#define fpgetprec() ((fp_prec_t) \
((__fpgetreg(FP_PRC_REG) & FP_PRC_FLD) >> FP_PRC_OFF))
#define fpsetprec(m) ((fp_prec_t) \
__fpsetreg((m), FP_PRC_REG, FP_PRC_FLD, FP_PRC_OFF))
#define fpgetmask() ((fp_except_t) \
((~__fpgetreg(FP_MSKS_REG) & FP_MSKS_FLD) >> FP_MSKS_OFF))
#define fpsetmask(m) ((fp_except_t) \
(~__fpsetreg(~(m), FP_MSKS_REG, FP_MSKS_FLD, FP_MSKS_OFF)) & \
(FP_MSKS_FLD >> FP_MSKS_OFF))
#define fpgetsticky() ((fp_except_t) \
((__fpgetreg(FP_STKY_REG) & FP_STKY_FLD) >> FP_STKY_OFF))
#define fpresetsticky(m) ((fp_except_t) \
__fpsetreg(0, FP_STKY_REG, (m), FP_STKY_OFF))
#define fpsetsticky(m) fpresetsticky(m)
#endif /* !_FLOATINGPOINT_H_ */