__setfpucw - set FPU control word on i386 architecture (obsolete)
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 (3), fegetround (3), and the floating-point environment, like fesetround (3), fegetenv (3), feholdexcept (3), fesetenv (3), and FPU exception handling, like feupdateenv (3), feclearexcept (3), fegetexceptflag (3), feraiseexcept (3), and fesetexceptflag (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.
Set FPU control word on the i386 architecture to
- extended precision
- rounding to nearest
- exceptions on overflow, zero divide and NaN
September 15, 2017
February 9, 2018
December 2, 2018