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), 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.

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 4.16 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/.


  Written Sat Mar  8 10:35:08 MEZ 1997 by
J. "MUFTI" Scheurich (mufticsv.ica.uni-stuttgart.de)

%%%LICENSE_START(GPL_NOVERSION_ONELINE)
This page is licensed under the GNU General Public License
%%%LICENSE_END