c5a82dd848
* Implement fpgetsticky() for alpha.
* Direct fpsetsticky() and fp{get,set}mask() into alpha kernel via sysarch(2).
* Define new sysarch(2) stub for above and install and distribute sysarch.h
for alpha. (The fpcr IS user mode r/w, but for reasons beyond the scope
of a commit message kernel calls are needed.) And much kernel Magick is
required before these do anything, but this way programs compiled under
1.4 will DTRT on future snapshots and releases.
132 lines
3.9 KiB
Groff
132 lines
3.9 KiB
Groff
.\" $NetBSD: fpgetmask.3,v 1.1 1999/04/30 00:58:31 ross Exp $
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.\"
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.\" Copyright (c) 1999 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Ross Harvey.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd April 29, 1999
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.Dt FPGETMASK 3
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.Os
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.Sh NAME
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.Nm fpgetmask ,
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.Nm fpgetround ,
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.Nm fpgetsticky ,
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.Nm fpsetmask ,
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.Nm fpsetround ,
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.Nm fpsetsticky
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.Nd IEEE FP mode control
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.Fd #include <ieeefp.h>
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.Ft fp_except
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.Fn fpgetmask void
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.Ft fp_rnd
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.Fn fpgetround void
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.Ft fp_except
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.Fn fpgetsticky void
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.Ft fp_except
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.Fn fpsetmask fp_except\ mask
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.Ft fp_rnd
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.Fn fpsetround fp_rnd\ rnd_dir
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.Ft fp_except
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.Fn fpsetsticky fp_except\ sticky
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.Sh DESCRIPTION
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A rounding mode is one of
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.Dv FP_RZ , FP_RM , FP_RN ,
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or
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.Dv FP_RP ,
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for rounding towards zero, rounding
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.Pq Em Minus infinity
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down, rounding to
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.Em nearest ,
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and rounding
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.Pq Em Plus infinity
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up.
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The default mode is
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.Dv FP_RN .
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.Pp
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An
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.Ft fp_except
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value is a bitmask specifying an exception type and containing any of
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the values listed below.
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.Bl -column -offset indent FP_X_UFLxx
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.It Dv FP_X_INV Ta Invalid\ Operation
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.It Dv FP_X_DZ Ta Division\ by\ zero
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.It Dv FP_X_OFL Ta Overflow
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.It Dv FP_X_UFL Ta Underflow
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.It Dv FP_X_IMP Ta Imprecision (inexact)
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.It Dv FP_X_IOV Ta Integer\ Overflow
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.El
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.Pp
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.Pp
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The
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.Fn fpsetmask
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function will cause future operations with the specified result status to
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raise the
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.Dv SIGFPE
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exception.
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The
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.Fn fpsetround
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function will cause future operations to use the specified dynamic mode.
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.Bl -tag -width Note:x
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.It Em Note:
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On some architectures, instructions can optionally specify static
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rounding modes and exception enables that will supersede the specified
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dynamic mode. On other architectures, these features may not be fully
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supported.
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.El
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.Pp
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The
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.Fn fpsetsticky
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function will set or clear the specified exception history bits.
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.Sh RETURN VALUES
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The
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.Fn fpgetround
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and
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.Fn fpsetround
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functions return the
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.Pq previous
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rounding mode.
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The
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.Fn fpgetmask ,
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.Fn fpsetmask ,
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.Fn fpgetsticky ,
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and
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.Fn fpsetsticky
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functions return the
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.Pq previous
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exception mask and exception history bits.
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.Sh SEE ALSO
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.Xr sigaction 2
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