4f36d4ac99
Add cross-references to the elusive fpsetmask() function to various other man pages. Reviewed by: bde
177 lines
4.8 KiB
Groff
177 lines
4.8 KiB
Groff
.\" 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.
|
|
.\"
|
|
.\" @(#)fpgetround.3 1.0 (Berkeley) 9/23/93
|
|
.\" $Id: fpgetround.3,v 1.5 1997/04/13 14:19:59 bde Exp $
|
|
.\"
|
|
.Dd August 23, 1993
|
|
.Dt FPGETROUND 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm fpgetround ,
|
|
.Nm fpsetround ,
|
|
.Nm fpsetprec ,
|
|
.Nm fpgetprec ,
|
|
.Nm fpgetmask ,
|
|
.Nm fpsetmask ,
|
|
.Nm fpgetsticky ,
|
|
.Nm fpresetsticky
|
|
.Nd IEEE floating point interface
|
|
.Sh SYNOPSIS
|
|
.Fd #include <floatingpoint.h>
|
|
.Ft typedef enum {
|
|
.br
|
|
.Fa FP_RN,
|
|
.Li /* round to nearest */
|
|
.br
|
|
.Fa FP_RM,
|
|
.Li /* round to minus infinity */
|
|
.br
|
|
.Fa FP_RP,
|
|
.Li /* round to plus infinity */
|
|
.br
|
|
.Fa FP_RZ,
|
|
.Li /* truncate */
|
|
.br
|
|
.Ft } fp_rnd_t;
|
|
.Pp
|
|
.Ft fp_rnd_t
|
|
.Fn fpgetround void
|
|
.Ft fp_rnd_t
|
|
.Fn fpsetround "fp_rnd_t direction"
|
|
.Pp
|
|
.nr fZ 0
|
|
.Ft typedef enum {
|
|
.br
|
|
.Fa FP_PS,
|
|
.Li /* 24 bit (single-precision) */
|
|
.br
|
|
.Fa FP_PRS,
|
|
.Li /* reserved */
|
|
.br
|
|
.Fa FP_PD,
|
|
.Li /* 53 bit (double-precision) */
|
|
.br
|
|
.Fa FP_PE,
|
|
.Li /* 64 bit (extended-precision) */
|
|
.br
|
|
.Ft } fp_prec_t;
|
|
.Pp
|
|
.Ft fp_prec_t
|
|
.Fn fpgetprec void
|
|
.Ft fp_prec_t
|
|
.Fn fpsetprec "fp_prec_t precision"
|
|
.Pp
|
|
.Fd #define fp_except_t int
|
|
.Fd #define FP_X_INV 0x01 /* invalid */
|
|
.Fd #define FP_X_OFL 0x08 /* overflow */
|
|
.Fd #define FP_X_UFL 0x10 /* underflow */
|
|
.Fd #define FP_X_DZ 0x04 /* divide-by-zero */
|
|
.Fd #define FP_X_IMP 0x20 /* loss of precision */
|
|
.Fd #define FP_X_DNML 0x02 /* denormal */
|
|
.Ft fp_except_t
|
|
.Fn fpgetmask void
|
|
.Ft fp_except_t
|
|
.Fn fpsetmask "fp_except_t mask"
|
|
.Ft fp_except_t
|
|
.Fn fpgetsticky void
|
|
.Ft fp_except_t
|
|
.Fn fpresetsticky "fp_except_t sticky"
|
|
.Sh DESCRIPTION
|
|
When a floating point exception is detected, the exception sticky flag is
|
|
set and the exception mask is tested. If the mask is set, then a trap
|
|
occurs. These routines allow both setting the floating point exception
|
|
masks, and resetting the exception sticky flags after an exception is
|
|
detected. In addition, they allow setting the floating point rounding mode
|
|
and precision.
|
|
.Pp
|
|
The
|
|
.Fn fpgetround
|
|
function
|
|
returns the current floating point rounding mode.
|
|
.Pp
|
|
The
|
|
.Fn fpsetround
|
|
function
|
|
sets the floating point rounding mode and returns
|
|
the previous mode.
|
|
.Pp
|
|
The
|
|
.Fn fpgetprec
|
|
function
|
|
returns the current floating point precision.
|
|
.Pp
|
|
The
|
|
.Fn fpsetprec
|
|
function
|
|
sets the floating point precision and returns
|
|
the previous precision.
|
|
.Pp
|
|
The
|
|
.Fn fpgetmask
|
|
function
|
|
returns the current floating point exception masks.
|
|
.Pp
|
|
The
|
|
.Fn fpsetmask
|
|
function
|
|
sets the floating point exception masks and returns the
|
|
previous masks.
|
|
.Pp
|
|
The
|
|
.Fn fpgetsticky
|
|
function
|
|
returns the current floating point sticky flags.
|
|
.Pp
|
|
The
|
|
.Fn fpresetsticky
|
|
function
|
|
clears the floating point sticky flags and returns
|
|
the previous flags.
|
|
.Pp
|
|
Sample code which prevents a trap on divide-by-zero:
|
|
.Bd -literal -offset indent
|
|
fpsetmask(~FP_X_DZ);
|
|
a = 1.0;
|
|
b = 0;
|
|
c = a / b;
|
|
fpresetsticky(FP_X_DZ);
|
|
fpsetmask(FP_X_DZ);
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr isnan 3
|
|
.Sh CAVEAT
|
|
After a floating point exception and before a mask is set, the sticky
|
|
flags must be reset. If another exception occurs before the sticky
|
|
flags are reset, then a wrong exception type may be signaled.
|
|
.Sh HISTORY
|
|
These routines are based on SysV/386 routines of the same name.
|