__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 (float-
ing-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 round-
ing modes, like fegetround(3), fesetround(3), and the floating-point
environment, like fegetenv(3), feholdexcept(3), fesetenv(3), feupda-
teenv(3), and FPU exception handling, like feclearexcept(3), fegetex-
ceptflag(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.
EXAMPLES
__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 5.10 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
https://www.kernel.org/doc/man-pages/.
Linux 2020-06-09 __SETFPUCW(3)
Generated by dwww version 1.14 on Thu Jan 23 04:47:02 CET 2025.