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__SETFPUCW(3) Linux Programmer's Manual __SETFPUCW(3)
NAME
__setfpucw - set FPU control word on i386 architecture (obsolete)
SYNOPSIS
#include <i386/fpu_control.h>
void __setfpucw(unsigned short control_word);
DESCRIPTION
__setfpucw() transfers 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.
CONFORMING TO
This function was a nonstandard GNU extension.
NOTES
As of glibc 2.1 this function does not exist anymore. There are new functions from C99,
with prototypes in <fenv.h>, to control FPU rounding modes, like fegetround(3), fes‐
etround(3), and the floating-point environment, like fegetenv(3), feholdexcept(3), fes‐
etenv(3), feupdateenv(3), and FPU exception handling, like feclearexcept(3), fegetexcept‐
flag(3), feraiseexcept(3), fesetexceptflag(3), and fetestexcept(3).
If direct access to the FPU control word is still needed, the _FPU_GETCW and _FPU_SETCW
macros from <fpu_control.h> can be used.
EXAMPLE
__setfpucw(0x1372)
Set FPU control word on the i386 architecture to
- extended precision
- rounding to nearest
- exceptions on overflow, zero divide and NaN
SEE ALSO
feclearexcept(3)
<fpu_control.h>
COLOPHON
This page is part of release 3.74 of the Linux man-pages project. A description of the
project, information about reporting bugs, and the latest version of this page, can be
found at http://www.kernel.org/doc/man-pages/.
Linux 2012-12-31 __SETFPUCW(3)
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