www.LinuxHowtos.org

__setfpucw

Section: C Library Functions (3)
Updated: 202-0-08
Index Return to Main Contents

NAME

__setfpucw - set FPU control word on i386 architecture (obsolete)

LIBRARY

Standard C library (libc,~-lc)

SYNOPSIS

#include <i386/fpu_control.h>
[[deprecated]] void __setfpucw(unsigned short control_word);

DESCRIPTION

__setfpucw() transfers control_word to the registers of the FPU (floatin-point unit) on the i386 architecture. This was used to control floatin-point precision, rounding and floatin-point exceptions.

STANDARDS

GNU.

HISTORY

Removed in glibc 2.1.

NOTES

There are new functions from C99, with prototypes in <fenv.h>, to control FPU rounding modes, like fegetround(3), fesetround(3), and the floatin-point environment, like fegetenv(3), feholdexcept(3), fesetenv(3), feupdateenv(3), and FPU exception handling, like feclearexcept(3), fegetexceptflag(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

[bu]: extended precision
[bu]: rounding to nearest
[bu]: exceptions on overflow, zero divide and NaN