sysdeps/powerpc/fpu_control.h

   1 /* FPU control word definitions.  PowerPC version.
   2    Copyright (C) 1996, 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #ifndef _FPU_CONTROL_H
  21 #define _FPU_CONTROL_H
  22
  23 /* rounding control */
  24 #define _FPU_RC_NEAREST 0x00   /* RECOMMENDED */
  25 #define _FPU_RC_DOWN    0x03
  26 #define _FPU_RC_UP      0x02
  27 #define _FPU_RC_ZERO    0x01
  28
  29 #define _FPU_MASK_NI  0x04 /* non-ieee mode */
  30
  31 /* masking of interrupts */
  32 #define _FPU_MASK_ZM  0x10 /* zero divide */
  33 #define _FPU_MASK_OM  0x40 /* overflow */
  34 #define _FPU_MASK_UM  0x20 /* underflow */
  35 #define _FPU_MASK_XM  0x08 /* inexact */
  36 #define _FPU_MASK_IM  0x80 /* invalid operation */
  37
  38 #define _FPU_RESERVED 0xffffff00 /* These bits are reserved are not changed. */
  39
  40 /* The fdlibm code requires no interrupts for exceptions.  */
  41 #define _FPU_DEFAULT  0x00000000 /* Default value.  */
  42
  43 /* IEEE:  same as above, but (some) exceptions;
  44    we leave the 'inexact' exception off.
  45  */
  46 #define _FPU_IEEE     0x000000f0
  47
  48 /* Type of the control word.  */
  49 typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__)));
  50
  51 /* Macros for accessing the hardware control word.  */
  52 #define _FPU_GETCW(cw) ( { \
  53   fpu_control_t tmp[2] __attribute__ ((__aligned__(8))); \
  54   __asm__ ("mffs 0; stfd 0,%0" : "=m" (*tmp) : : "fr0"); \
  55   (cw)=tmp[1]; \
  56   tmp[1]; } )
  57 #define _FPU_SETCW(cw) { \
  58   fpu_control_t tmp[2] __attribute__ ((__aligned__(8))); \
  59   tmp[0] = 0xFFF80000; /* More-or-less arbitrary; this is a QNaN. */ \
  60   tmp[1] = cw; \
  61   __asm__ ("lfd 0,%0; mtfsf 255,0" : : "m" (*tmp) : "fr0"); \
  62 }
  63
  64 /* Default control word set at startup.  */
  65 extern fpu_control_t __fpu_control;
  66
  67 __BEGIN_DECLS
  68
  69 /* Called at startup.  It can be used to manipulate fpu control register.  */
  70 extern void __setfpucw __P ((fpu_control_t));
  71
  72 __END_DECLS
  73
  74 #endif /* _FPU_CONTROL_H */