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.\" Written Sat Mar 8 10:35:08 MEZ 1997 by
.\" J. "MUFTI" Scheurich (mufti@csv.ica.uni-stuttgart.de)
.\"
.\" SPDX-License-Identifier: GPL-1.0-or-later
.\"
.TH __setfpucw 3 2023-03-30 "Linux man-pages 6.04"
.SH NAME
__setfpucw \- set FPU control word on i386 architecture (obsolete)
.SH LIBRARY
Standard C library
.RI ( libc ", " \-lc )
.SH SYNOPSIS
.nf
.B #include <i386/fpu_control.h>
.PP
.BI "[[deprecated]] void __setfpucw(unsigned short " control_word );
.fi
.SH DESCRIPTION
.BR __setfpucw ()
transfers
.I control_word
to the registers of the FPU (floating-point unit) on the i386 architecture.
This was used to control floating-point precision,
rounding and floating-point exceptions.
.SH STANDARDS
GNU.
.SH HISTORY
Removed in glibc 2.1.
.SH NOTES
There are new functions from C99, with prototypes in
.IR <fenv.h> ,
to control FPU rounding modes, like
.BR fegetround (3),
.BR fesetround (3),
and the floating-point environment, like
.BR fegetenv (3),
.BR feholdexcept (3),
.BR fesetenv (3),
.BR feupdateenv (3),
and FPU exception handling, like
.BR feclearexcept (3),
.BR fegetexceptflag (3),
.BR feraiseexcept (3),
.BR fesetexceptflag (3),
and
.BR fetestexcept (3).
.PP
If direct access to the FPU control word is still needed, the
.B _FPU_GETCW
and
.B _FPU_SETCW
macros from
.I <fpu_control.h>
can be used.
.SH EXAMPLES
.B __setfpucw(0x1372)
.PP
Set FPU control word on the i386 architecture to
.RS
.PD 0
.IP \[bu] 3
extended precision
.IP \[bu]
rounding to nearest
.IP \[bu]
exceptions on overflow, zero divide and NaN
.PD
.RE
.SH SEE ALSO
.BR feclearexcept (3)
.PP
.I <fpu_control.h>
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