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Diffstat (limited to 'man/man3/fma.3')
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diff --git a/man/man3/fma.3 b/man/man3/fma.3 new file mode 100644 index 000000000..a4d2330a6 --- /dev/null +++ b/man/man3/fma.3 @@ -0,0 +1,167 @@ +'\" t +.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) +.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk +.\" <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: GPL-1.0-or-later +.\" +.\" Modified 2004-11-15, Added further text on FLT_ROUNDS +.\" as suggested by AEB and Fabian Kreutz +.\" +.TH fma 3 (date) "Linux man-pages (unreleased)" +.SH NAME +fma, fmaf, fmal \- floating-point multiply and add +.SH LIBRARY +Math library +.RI ( libm ", " \-lm ) +.SH SYNOPSIS +.nf +.B #include <math.h> +.P +.BI "double fma(double " x ", double " y ", double " z ); +.BI "float fmaf(float " x ", float " y ", float " z ); +.BI "long double fmal(long double " x ", long double " y ", long double " z ); +.fi +.P +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.P +.BR fma (), +.BR fmaf (), +.BR fmal (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L +.fi +.SH DESCRIPTION +These functions compute +.IR x " * " y " + " z . +The result is rounded as one ternary operation according to the +current rounding mode (see +.BR fenv (3)). +.SH RETURN VALUE +These functions return the value of +.IR x " * " y " + " z , +rounded as one ternary operation. +.P +If +.I x +or +.I y +is a NaN, a NaN is returned. +.P +If +.I x +times +.I y +is an exact infinity, and +.I z +is an infinity with the opposite sign, +a domain error occurs, +and a NaN is returned. +.P +.\" 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. +If one of +.I x +or +.I y +is an infinity, the other is 0, and +.I z +is not a NaN, +a domain error occurs, and +a NaN is returned. +.\" POSIX.1 says that a NaN or an implementation-defined value shall +.\" be returned for this case. +.P +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. +a domain error occurs, and +a NaN is returned. +.P +If +.I x +times +.I y +is not an infinity times zero (or vice versa), and +.I z +is a NaN, +a NaN is returned. +.P +If the result overflows, +a range error occurs, and +an infinity with the correct sign is returned. +.P +If the result underflows, +a range error occurs, and +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. +.P +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. +.P +These functions do not set +.IR errno . +.\" FIXME . Is it intentional that these functions do not set errno? +.\" Bug raised: https://www.sourceware.org/bugzilla/show_bug.cgi?id=6801 +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR fma (), +.BR fmaf (), +.BR fmal () +T} Thread safety MT-Safe +.TE +.SH STANDARDS +C11, POSIX.1-2008. +.SH HISTORY +glibc 2.1. +C99, POSIX.1-2001. +.SH SEE ALSO +.BR remainder (3), +.BR remquo (3) |