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diff --git a/man-pages-posix-2013/man3p/fma.3p b/man-pages-posix-2013/man3p/fma.3p new file mode 100644 index 0000000..75ae21e --- /dev/null +++ b/man-pages-posix-2013/man3p/fma.3p @@ -0,0 +1,209 @@ +'\" et +.TH FMA "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. + +.SH NAME +fma, +fmaf, +fmal +\(em floating-point multiply-add +.SH SYNOPSIS +.LP +.nf +#include <math.h> +.P +double fma(double \fIx\fP, double \fIy\fP, double \fIz\fP); +float fmaf(float \fIx\fP, float \fIy\fP, float \fIz\fP); +long double fmal(long double \fIx\fP, long double \fIy\fP, long double \fIz\fP); +.fi +.SH DESCRIPTION +The functionality described on this reference page is aligned with the +ISO\ C standard. Any conflict between the requirements described here and the +ISO\ C standard is unintentional. This volume of POSIX.1\(hy2008 defers to the ISO\ C standard. +.P +These functions shall compute (\fIx\fR\ *\ \fIy\fR)\ +\ \fIz\fR, +rounded as one ternary operation: they shall compute the value (as if) +to infinite precision and round once to the result format, according to +the rounding mode characterized by the value of FLT_ROUNDS. +.P +An application wishing to check for error situations should set +.IR errno +to zero and call +.IR feclearexcept (FE_ALL_EXCEPT) +before calling these functions. On return, if +.IR errno +is non-zero or \fIfetestexcept\fR(FE_INVALID | FE_DIVBYZERO | +FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred. +.SH "RETURN VALUE" +Upon successful completion, these functions shall return +(\fIx\fR\ *\ \fIy\fR)\ + \fIz\fR, rounded as one ternary operation. +.P +If the result overflows or underflows, a range error may occur. +On systems that support the IEC 60559 Floating-Point option, if the +result overflows a range error shall occur. +.P +If +.IR x +or +.IR y +are NaN, a NaN shall be returned. +.P +If +.IR x +multiplied by +.IR y +is an exact infinity and +.IR z +is also an infinity but with the opposite sign, a domain error shall +occur, and either a NaN (if supported), or an implementation-defined +value shall be returned. +.P +If one of +.IR x +and +.IR y +is infinite, the other is zero, and +.IR z +is not a NaN, a domain error shall occur, and either a NaN (if +supported), or an implementation-defined value shall be returned. +.P +If one of +.IR x +and +.IR y +is infinite, the other is zero, and +.IR z +is a NaN, a NaN shall be returned and a domain error may occur. +.P +If +.IR x *\c +.IR y +is not 0*Inf nor Inf*0 and +.IR z +is a NaN, a NaN shall be returned. +.SH ERRORS +These functions shall fail if: +.IP "Domain\ Error" 12 +The value of +.IR x *\c +.IR y +\c +.IR z +is invalid, or the value +.IR x *\c +.IR y +is invalid and +.IR z +is not a NaN. +.RS 12 +.P +If the integer expression (\fImath_errhandling\fR & MATH_ERRNO) is +non-zero, then +.IR errno +shall be set to +.BR [EDOM] . +If the integer expression (\fImath_errhandling\fR & MATH_ERREXCEPT) is +non-zero, then the invalid floating-point exception shall be raised. +.RE +.IP "Range\ Error" 12 +The result overflows. +.RS 12 +.P +If the integer expression (\fImath_errhandling\fR & MATH_ERRNO) is +non-zero, then +.IR errno +shall be set to +.BR [ERANGE] . +If the integer expression (\fImath_errhandling\fR & MATH_ERREXCEPT) is +non-zero, then the overflow floating-point exception shall be raised. +.RE +.br +.P +These functions may fail if: +.IP "Domain\ Error" 12 +The value +.IR x *\c +.IR y +is invalid and +.IR z +is a NaN. +.RS 12 +.P +If the integer expression (\fImath_errhandling\fR & MATH_ERRNO) is +non-zero, then +.IR errno +shall be set to +.BR [EDOM] . +If the integer expression (\fImath_errhandling\fR & MATH_ERREXCEPT) is +non-zero, then the invalid floating-point exception shall be raised. +.RE +.IP "Range\ Error" 12 +The result underflows. +.RS 12 +.P +If the integer expression (\fImath_errhandling\fR & MATH_ERRNO) is +non-zero, then +.IR errno +shall be set to +.BR [ERANGE] . +If the integer expression (\fImath_errhandling\fR & MATH_ERREXCEPT) is +non-zero, then the underflow floating-point exception shall be raised. +.RE +.IP "Range\ Error" 12 +The result overflows. +.RS 12 +.P +If the integer expression (\fImath_errhandling\fR & MATH_ERRNO) is +non-zero, then +.IR errno +shall be set to +.BR [ERANGE] . +If the integer expression (\fImath_errhandling\fR & MATH_ERREXCEPT) is +non-zero, then the overflow floating-point exception shall be raised. +.RE +.LP +.IR "The following sections are informative." +.SH EXAMPLES +None. +.SH "APPLICATION USAGE" +On error, the expressions (\fImath_errhandling\fR & MATH_ERRNO) and +(\fImath_errhandling\fR & MATH_ERREXCEPT) are independent of each +other, but at least one of them must be non-zero. +.SH RATIONALE +In many cases, clever use of floating (\fIfused\fR) multiply-add leads +to much improved code; but its unexpected use by the compiler can +undermine carefully written code. The FP_CONTRACT macro can be used to +disallow use of floating multiply-add; and the +\fIfma\fR() +function guarantees its use where desired. Many current machines +provide hardware floating multiply-add instructions; software +implementation can be used for others. +.SH "FUTURE DIRECTIONS" +None. +.SH "SEE ALSO" +.IR "\fIfeclearexcept\fR\^(\|)", +.IR "\fIfetestexcept\fR\^(\|)" +.P +The Base Definitions volume of POSIX.1\(hy2008, +.IR "Section 4.19" ", " "Treatment of Error Conditions for Mathematical Functions", +.IR "\fB<math.h>\fP" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, Copyright (C) 2013 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.unix.org/online.html . + +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |