man3/__setfpucw.3

   1 .\" Written Sat Mar  8 10:35:08 MEZ 1997 by J. "MUFTI" Scheurich (mufti@csv.ica.uni-stuttgart.de)
   2 .TH __SETFPUCW 3 1997-03-08 "i386 Linux Man Page" "Linux Programmer's Manual"
   3 .SH NAME
   4 __setfpucw \- set fpu control word on i386 architecture (obsolete)
   5 .SH SYNOPSIS
   6 .B #include <i386/fpu_control.h>
   7 .sp
   8 .BI "void __setfpucw((unsigned short) " control_word );
   9 .br
  10 .SH DESCRIPTION
  11 .B __setfpucw
  12 transfers
  13 .I control_word
  14 to the registers of the fpu (floating point unit) on i386 architecture. This
  15 was used to control floating point precision, rounding and floating point
  16 exceptions.
  17 .SH EXAMPLE
  18
  19 .BR __setfpucw(0x1372)
  20
  21 Set fpu control word on i386 architecture to
  22 .br
  23      - extended precision
  24 .br
  25      - rounding to nearest
  26 .br
  27      - exceptions on overflow, zero divide and NaN
  28 .br
  29 .SH AVAILABILITY
  30 As of glibc 2.1 this function does not exist anymore.
  31 There are new functions from ISO C99, with prototypes in
  32 .IR /usr/include/fenv.h ,
  33 to control fpu rounding modes, like
  34 .IR fegetround ,
  35 .IR fesetround ,
  36 and the floating point environment, like
  37 .IR fegetenv ,
  38 .IR feholdexcept ,
  39 .IR fesetenv ,
  40 .IR feupdateenv
  41 and fpu exception handling, like
  42 .IR feclearexcept ,
  43 .IR fegetexceptflag ,
  44 .IR feraiseexcept ,
  45 .IR fesetexceptflag ,
  46 .IR fetestexcept .
  47 .PP
  48 If direct acces to the FPU control word is still needed, the _FPU_GETCW
  49 and _FPU_SETCW macros from
  50 .I /usr/include/fpu_control.h
  51 can be used.
  52 .SH "SEE ALSO"
  53 .BR feclearexcept (3)
  54 .br
  55 .IR /usr/include/i386/fpu_control.h