libm/include/i387/fenv.h

/*-
 * Copyright (c) 2004-2005 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: src/lib/msun/i387/fenv.h,v 1.4 2005/03/17 22:21:46 das Exp $
 */

#ifndef	_FENV_H_
#define	_FENV_H_

#include <sys/types.h>

__BEGIN_DECLS

/*                   
 * To preserve binary compatibility with FreeBSD 5.3, we pack the
 * mxcsr into some reserved fields, rather than changing sizeof(fenv_t).
 */
typedef struct {
	__uint16_t	__control;
	__uint16_t      __mxcsr_hi;
	__uint16_t	__status;
	__uint16_t      __mxcsr_lo;
	__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)

/* Default floating-point environment */
extern const fenv_t	__fe_dfl_env;
#define	FE_DFL_ENV	(&__fe_dfl_env)

/* C99 floating-point exception functions */
int feclearexcept(int excepts);
int fegetexceptflag(fexcept_t *flagp, int excepts);
int fesetexceptflag(const fexcept_t *flagp, int excepts);
/* feraiseexcept does not set the inexact flag on overflow/underflow */
int feraiseexcept(int excepts);
int fetestexcept(int excepts);

/* C99 rounding control functions */
int fegetround(void);
int fesetround(int round);

/* C99 floating-point environment functions */
int fegetenv(fenv_t *__envp);
int feholdexcept(fenv_t *__envp);
int fesetenv(const fenv_t *envp);
int feupdateenv(const fenv_t *__envp);

#if __BSD_VISIBLE
/* Additional support functions to set/query floating point traps */
int feenableexcept(int __mask);
int fedisableexcept(int __mask);
int fegetexcept(void);

#endif /* __BSD_VISIBLE */

__END_DECLS

#endif	/* !_FENV_H_ */