freebsd-dev/lib/msun/i387/fenv.h
David Schultz f365db00e5 Mark all inline asms that read the floating-point control or status
registers as volatile.  Instructions that *wrote* to FP state were
already marked volatile, but apparently gcc has license to move
non-volatile asms past volatile asms.  This broke amd64's feupdateenv
at -O2 due to a WAR conflict between fnstsw and fldenv there.
2005-01-14 07:09:23 +00:00

225 lines
4.8 KiB
C

/*-
* Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* $FreeBSD$
*/
#ifndef _FENV_H_
#define _FENV_H_
#include <sys/cdefs.h>
#include <sys/_types.h>
typedef struct {
__uint32_t __control;
__uint32_t __status;
__uint32_t __tag;
char __other[16];
} fenv_t;
typedef __uint16_t fexcept_t;
/* Exception flags */
#define FE_INVALID 0x01
#define FE_DENORMAL 0x02
#define FE_DIVBYZERO 0x04
#define FE_OVERFLOW 0x08
#define FE_UNDERFLOW 0x10
#define FE_INEXACT 0x20
#define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \
FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
/* Rounding modes */
#define FE_TONEAREST 0x0000
#define FE_DOWNWARD 0x0400
#define FE_UPWARD 0x0800
#define FE_TOWARDZERO 0x0c00
#define _ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \
FE_UPWARD | FE_TOWARDZERO)
__BEGIN_DECLS
/* Default floating-point environment */
extern const fenv_t __fe_dfl_env;
#define FE_DFL_ENV (&__fe_dfl_env)
#define __fldcw(__cw) __asm __volatile("fldcw %0" : : "m" (__cw))
#define __fldenv(__env) __asm __volatile("fldenv %0" : : "m" (__env))
#define __fnclex() __asm __volatile("fnclex")
#define __fnstenv(__env) __asm __volatile("fnstenv %0" : "=m" (*(__env)))
#define __fnstcw(__cw) __asm __volatile("fnstcw %0" : "=m" (*(__cw)))
#define __fnstsw(__sw) __asm __volatile("fnstsw %0" : "=am" (*(__sw)))
#define __fwait() __asm __volatile("fwait")
static __inline int
feclearexcept(int __excepts)
{
fenv_t __env;
if (__excepts == FE_ALL_EXCEPT) {
__fnclex();
} else {
__fnstenv(&__env);
__env.__status &= ~__excepts;
__fldenv(__env);
}
return (0);
}
static __inline int
fegetexceptflag(fexcept_t *__flagp, int __excepts)
{
int __status;
__fnstsw(&__status);
*__flagp = __status & __excepts;
return (0);
}
static __inline int
fesetexceptflag(const fexcept_t *__flagp, int __excepts)
{
fenv_t __env;
__fnstenv(&__env);
__env.__status &= ~__excepts;
__env.__status |= *__flagp & __excepts;
__fldenv(__env);
return (0);
}
static __inline int
feraiseexcept(int __excepts)
{
fexcept_t __ex = __excepts;
fesetexceptflag(&__ex, __excepts);
__fwait();
return (0);
}
static __inline int
fetestexcept(int __excepts)
{
int __status;
__fnstsw(&__status);
return (__status & __excepts);
}
static __inline int
fegetround(void)
{
int __control;
__fnstcw(&__control);
return (__control & _ROUND_MASK);
}
static __inline int
fesetround(int __round)
{
int __control;
if (__round & ~_ROUND_MASK)
return (-1);
__fnstcw(&__control);
__control &= ~_ROUND_MASK;
__control |= __round;
__fldcw(__control);
return (0);
}
static __inline int
fegetenv(fenv_t *__envp)
{
int __control;
/*
* fnstenv masks all exceptions, so we need to save and
* restore the control word to avoid this side effect.
*/
__fnstcw(&__control);
__fnstenv(__envp);
__fldcw(__control);
return (0);
}
static __inline int
feholdexcept(fenv_t *__envp)
{
__fnstenv(__envp);
__fnclex();
return (0);
}
static __inline int
fesetenv(const fenv_t *__envp)
{
__fldenv(*__envp);
return (0);
}
static __inline int
feupdateenv(const fenv_t *__envp)
{
int __status;
__fnstsw(&__status);
__fldenv(*__envp);
feraiseexcept(__status & FE_ALL_EXCEPT);
return (0);
}
#if __BSD_VISIBLE
static __inline int
fesetmask(int __mask)
{
int __control;
__fnstcw(&__control);
__mask = (__control | FE_ALL_EXCEPT) & ~__mask;
__fldcw(__mask);
return (~__control & FE_ALL_EXCEPT);
}
static __inline int
fegetmask(void)
{
int __control;
__fnstcw(&__control);
return (~__control & FE_ALL_EXCEPT);
}
#endif /* __BSD_VISIBLE */
__END_DECLS
#endif /* !_FENV_H_ */