2004-11-03 13:51:07 +00:00
|
|
|
.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
|
2008-08-01 05:26:17 +00:00
|
|
|
.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
|
|
|
|
.\" <mtk.manpages@gmail.com>
|
2004-11-03 13:51:07 +00:00
|
|
|
.\" Distributed under GPL, 2002-07-27 Walter Harms
|
2004-11-15 10:55:23 +00:00
|
|
|
.\" Modified 2004-11-15, Added further text on FLT_ROUNDS
|
|
|
|
.\" as suggested by AEB and Fabian Kreutz
|
2004-11-03 13:51:07 +00:00
|
|
|
.\"
|
_exit.2, brk.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, getdtablesize.2, gethostname.2, getpagesize.2, getsid.2, killpg.2, mknod.2, mknodat.2, poll.2, posix_fadvise.2, pread.2, readlink.2, setpgid.2, setreuid.2, sigaltstack.2, stat.2, symlink.2, sync.2, truncate.2, vfork.2, wait.2, wait4.2, a64l.3, abs.3, acos.3, acosh.3, asin.3, asinh.3, atan.3, atan2.3, atoi.3, cbrt.3, ceil.3, copysign.3, cosh.3, dirfd.3, div.3, ecvt.3, erf.3, erfc.3, exp.3, exp2.3, fabs.3, fdim.3, ffs.3, floor.3, fma.3, fmax.3, fmin.3, fmod.3, fpclassify.3, frexp.3, ftw.3, fwide.3, gcvt.3, getcwd.3, getdate.3, getgrent.3, gethostid.3, getpass.3, getpwent.3, getsubopt.3, getw.3, hypot.3, ilogb.3, index.3, isalpha.3, isgreater.3, iswblank.3, j0.3, ldexp.3, lockf.3, log.3, log10.3, log1p.3, logb.3, lrint.3, lround.3, mkstemp.3, mktemp.3, modf.3, mq_receive.3, mq_send.3, nan.3, nextafter.3, posix_fallocate.3, posix_memalign.3, printf.3, qecvt.3, random.3, realpath.3, remainder.3, remquo.3, rint.3, round.3, scalb.3, scalbln.3, scanf.3, siginterrupt.3, signbit.3, sigset.3, sinh.3, sqrt.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strfry.3, strpbrk.3, strsep.3, strspn.3, strstr.3, strtod.3, strtok.3, strtol.3, strtoul.3, strxfrm.3, tanh.3, tgamma.3, trunc.3, ttyslot.3, ualarm.3, usleep.3, wprintf.3, armscii-8.7, cp1251.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-3.7, iso_8859-5.7, iso_8859-6.7, iso_8859-8.7, koi8-u.7: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-09-19 17:19:13 +00:00
|
|
|
.TH FMA 3 2010-09-20 "" "Linux Programmer's Manual"
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH NAME
|
|
|
|
fma, fmaf, fmal \- floating-point multiply and add
|
|
|
|
.SH SYNOPSIS
|
|
|
|
.nf
|
|
|
|
.B #include <math.h>
|
|
|
|
.sp
|
|
|
|
.BI "double fma(double " x ", double " y ", double " z );
|
2004-11-11 17:28:42 +00:00
|
|
|
.br
|
2004-11-03 13:51:07 +00:00
|
|
|
.BI "float fmaf(float " x ", float " y ", float " z );
|
2004-11-11 17:28:42 +00:00
|
|
|
.br
|
2004-11-03 13:51:07 +00:00
|
|
|
.BI "long double fmal(long double " x ", long double " y ", long double " z );
|
|
|
|
.fi
|
|
|
|
.sp
|
2008-08-01 05:26:17 +00:00
|
|
|
Link with \fI\-lm\fP.
|
|
|
|
.sp
|
|
|
|
.in -4n
|
|
|
|
Feature Test Macro Requirements for glibc (see
|
|
|
|
.BR feature_test_macros (7)):
|
|
|
|
.in
|
|
|
|
.sp
|
|
|
|
.ad l
|
|
|
|
.BR fma (),
|
|
|
|
.BR fmaf (),
|
|
|
|
.BR fmal ():
|
2010-09-18 15:59:16 +00:00
|
|
|
.RS 4
|
2010-09-18 16:03:48 +00:00
|
|
|
_XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
|
|
|
|
_POSIX_C_SOURCE\ >=\ 200112L;
|
2010-09-18 15:59:16 +00:00
|
|
|
.br
|
|
|
|
or
|
2008-08-01 05:26:17 +00:00
|
|
|
.I cc\ -std=c99
|
2010-09-18 15:59:16 +00:00
|
|
|
.RE
|
|
|
|
.ad
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH DESCRIPTION
|
2007-04-12 22:42:49 +00:00
|
|
|
The
|
2005-10-19 07:07:02 +00:00
|
|
|
.BR fma ()
|
2004-11-03 13:51:07 +00:00
|
|
|
function computes
|
|
|
|
.IR x " * " y " + " z .
|
2008-08-01 05:26:17 +00:00
|
|
|
The result is rounded as one ternary operation according to the
|
2008-08-07 11:15:34 +00:00
|
|
|
current rounding mode (see
|
|
|
|
.BR fenv (3)).
|
2008-08-01 05:26:17 +00:00
|
|
|
.SH RETURN VALUE
|
|
|
|
These functions return the value of
|
|
|
|
.IR x " * " y " + " z ,
|
|
|
|
rounded as one ternary operation.
|
|
|
|
|
|
|
|
If
|
|
|
|
.I x
|
|
|
|
or
|
|
|
|
.I y
|
|
|
|
is a NaN, a NaN is returned.
|
|
|
|
|
|
|
|
If
|
|
|
|
.I x
|
|
|
|
times
|
|
|
|
.I y
|
|
|
|
is an exact infinity, and
|
|
|
|
.I z
|
|
|
|
is an infinity with the opposite sign,
|
2008-08-04 16:00:58 +00:00
|
|
|
a domain error occurs,
|
2008-08-01 05:26:17 +00:00
|
|
|
and a NaN is returned.
|
|
|
|
|
2008-09-29 11:42:58 +00:00
|
|
|
.\" POSIX.1-2008 allows some possible differences for the following two
|
|
|
|
.\" domain error cases, but on Linux they are treated the same (AFAICS).
|
|
|
|
.\" Nevertheless, we'll mirror POSIX.1 and describe the two cases
|
|
|
|
.\" separately.
|
2008-08-01 05:26:17 +00:00
|
|
|
If one of
|
|
|
|
.I x
|
|
|
|
or
|
|
|
|
.I y
|
|
|
|
is an infinity, the other is 0, and
|
|
|
|
.I z
|
|
|
|
is not a NaN,
|
2008-08-04 16:00:58 +00:00
|
|
|
a domain error occurs, and
|
2008-08-01 05:26:17 +00:00
|
|
|
a NaN is returned.
|
2008-09-29 11:42:58 +00:00
|
|
|
.\" POSIX.1 says that a NaN or an implementation-defined value shall
|
|
|
|
.\" be returned for this case.
|
2008-08-01 05:26:17 +00:00
|
|
|
|
|
|
|
If one of
|
|
|
|
.I x
|
|
|
|
or
|
|
|
|
.I y
|
|
|
|
is an infinity, and the other is 0, and
|
|
|
|
.I z
|
|
|
|
is a NaN,
|
|
|
|
.\" POSIX.1 makes the domain error optional for this case.
|
2008-08-04 16:00:58 +00:00
|
|
|
a domain error occurs, and
|
2008-08-01 05:26:17 +00:00
|
|
|
a NaN is returned.
|
|
|
|
|
|
|
|
If
|
|
|
|
.I x
|
|
|
|
times
|
|
|
|
.I y
|
2008-08-05 10:33:06 +00:00
|
|
|
is not an infinity times zero (or vice versa), and
|
2008-08-01 05:26:17 +00:00
|
|
|
.I z
|
|
|
|
is a NaN,
|
|
|
|
a NaN is returned.
|
|
|
|
|
|
|
|
If the result overflows,
|
2008-08-04 16:00:58 +00:00
|
|
|
a range error occurs, and
|
2008-08-01 05:26:17 +00:00
|
|
|
an infinity with the correct sign is returned.
|
|
|
|
|
|
|
|
If the result underflows,
|
2008-08-04 16:00:58 +00:00
|
|
|
a range error occurs, and
|
2008-08-01 05:26:17 +00:00
|
|
|
a signed 0 is returned.
|
|
|
|
.SH ERRORS
|
|
|
|
See
|
|
|
|
.BR math_error (7)
|
|
|
|
for information on how to determine whether an error has occurred
|
|
|
|
when calling these functions.
|
|
|
|
.PP
|
|
|
|
The following errors can occur:
|
|
|
|
.TP
|
|
|
|
Domain error: \fIx\fP * \fIy\fP + \fIz\fP, \
|
|
|
|
or \fIx\fP * \fIy\fP is invalid and \fIz\fP is not a NaN
|
|
|
|
.\" .I errno
|
|
|
|
.\" is set to
|
|
|
|
.\" .BR EDOM .
|
|
|
|
An invalid floating-point exception
|
|
|
|
.RB ( FE_INVALID )
|
|
|
|
is raised.
|
|
|
|
.TP
|
|
|
|
Range error: result overflow
|
|
|
|
.\" .I errno
|
|
|
|
.\" is set to
|
|
|
|
.\" .BR ERANGE .
|
|
|
|
An overflow floating-point exception
|
|
|
|
.RB ( FE_OVERFLOW )
|
|
|
|
is raised.
|
|
|
|
.TP
|
|
|
|
Range error: result underflow
|
|
|
|
.\" .I errno
|
|
|
|
.\" is set to
|
|
|
|
.\" .BR ERANGE .
|
|
|
|
An underflow floating-point exception
|
|
|
|
.RB ( FE_UNDERFLOW )
|
|
|
|
is raised.
|
|
|
|
.PP
|
|
|
|
These functions do not set
|
|
|
|
.IR errno .
|
|
|
|
.\" FIXME . Is it intentional that these functions do not set errno?
|
|
|
|
.\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6801
|
2008-08-11 17:13:47 +00:00
|
|
|
.SH VERSIONS
|
|
|
|
These functions first appeared in glibc in version 2.1.
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH "CONFORMING TO"
|
2008-08-01 05:26:17 +00:00
|
|
|
C99, POSIX.1-2001.
|
2004-11-03 13:51:07 +00:00
|
|
|
.SH "SEE ALSO"
|
|
|
|
.BR remainder (3),
|
|
|
|
.BR remquo (3)
|