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 #define _FPU_MASK_VXCVI 0x100 /* invalid operation for integer convert */
  38 #define _FPU_MASK_VXSQRT 0x200 /* invalid operation for square root */
  39 #define _FPU_MASK_VXSOFT 0x400 /* invalid operation raised by software */
  40
  41 #define _FPU_RESERVED 0xfffff800 /* These bits are reserved are not changed. */
  42
  43 /* The fdlibm code requires no interrupts for exceptions.  Don't
  44    change the rounding mode, it would break long double I/O!  */
  45 #define _FPU_DEFAULT  0x00000000 /* Default value.  */
  46
  47 /* IEEE:  same as above, but (some) exceptions;
  48    we leave the 'inexact' exception off.
  49  */
  50 #define _FPU_IEEE     0x000003f0
  51
  52 /* Type of the control word.  */
  53 typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__)));
  54
  55 /* Macros for accessing the hardware control word.  */
  56 #define _FPU_GETCW(cw) ( { \
  57   fpu_control_t tmp[2] __attribute__ ((__aligned__(8))); \
  58   __asm__ ("mffs 0; stfd 0,%0" : "=m" (*tmp) : : "fr0"); \
  59   tmp[1]; } )
  60 #define _FPU_SETCW(cw) { \
  61   fpu_control_t tmp[2] __attribute__ ((__aligned__(8))); \
  62   tmp[0] = 0xFFF80000; /* arbitrary, more-or-less */ \
  63   tmp[1] = cw; \
  64   __asm__ ("lfd 0,%0; mtfsf 255,0" : : "m" (*tmp) : "fr0"); \
  65 }
  66
  67 /* Default control word set at startup.  */
  68 extern fpu_control_t __fpu_control;
  69
  70 __BEGIN_DECLS
  71
  72 /* Called at startup.  It can be used to manipulate fpu control register.  */
  73 extern void __setfpucw __P ((fpu_control_t));
  74
  75 __END_DECLS
  76
  77 #endif /* _FPU_CONTROL_H */