sysdeps/powerpc/fpu/fpu_control.h

   1 /* FPU control word definitions.  PowerPC version.
   2    Copyright (C) 1996, 1997, 1998 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    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   union { double d; fpu_control_t cw[2]; } \
  54     tmp __attribute__ ((__aligned__(8))); \
  55   __asm__ ("mffs 0; stfd%U0 0,%0" : "=m" (tmp.d) : : "fr0"); \
  56   (__cw)=tmp.cw[1]; \
  57   tmp.cw[1]; } )
  58 #define _FPU_SETCW(__cw) { \
  59   union { double d; fpu_control_t cw[2]; } \
  60     tmp __attribute__ ((__aligned__(8))); \
  61   tmp.cw[0] = 0xFFF80000; /* More-or-less arbitrary; this is a QNaN. */ \
  62   tmp.cw[1] = __cw; \
  63   __asm__ ("lfd%U0 0,%0; mtfsf 255,0" : : "m" (tmp.d) : "fr0"); \
  64 }
  65
  66 /* Default control word set at startup.  */
  67 extern fpu_control_t __fpu_control;
  68
  69 #endif /* _FPU_CONTROL_H */