__setfpucw(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | CONFORMING TO | NOTES | EXAMPLES | SEE ALSO | COLOPHON

__SETFPUCW(3)           Linux Programmer's Manual          __SETFPUCW(3)

NAME         top

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

SYNOPSIS         top

       #include <i386/fpu_control.h>

       void __setfpucw(unsigned short control_word);

DESCRIPTION         top

       __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         top

       This function was a nonstandard GNU extension.

NOTES         top

       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), fesetround(3), and the
       floating-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         top

       __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         top

       feclearexcept(3)

       <fpu_control.h>

COLOPHON         top

       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)