__setfpucw - set FPU control word on i386 architecture (obsolete)
#include <i386/fpu_control.h>
void __setfpucw(unsigned short control_word);
__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.
This function was a nonstandard GNU extension.
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.
__setfpucw(0x1372)
Set FPU control word on the i386 architecture to
- extended precision
- rounding to nearest
- exceptions on overflow, zero divide and NaN
feclearexcept(3)
<fpu_control.h>