sysdeps/powerpc/fpu_control.h

   1 /* FPU control word definitions.  PowerPC version.
   2    Copyright (C) 1996-2013 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _FPU_CONTROL_H
  20 #define _FPU_CONTROL_H
  21
  22 #if defined _SOFT_FLOAT || defined __NO_FPRS__
  23
  24 # define _FPU_RESERVED 0xffffffff
  25 # define _FPU_DEFAULT  0x00000000 /* Default value.  */
  26 typedef unsigned int fpu_control_t;
  27 # define _FPU_GETCW(cw) (cw) = 0
  28 # define _FPU_SETCW(cw) (void) (cw)
  29 extern fpu_control_t __fpu_control;
  30
  31 #else /* PowerPC 6xx floating-point.  */
  32
  33 /* rounding control */
  34 # define _FPU_RC_NEAREST 0x00   /* RECOMMENDED */
  35 # define _FPU_RC_DOWN    0x03
  36 # define _FPU_RC_UP      0x02
  37 # define _FPU_RC_ZERO    0x01
  38
  39 # define _FPU_MASK_NI  0x04 /* non-ieee mode */
  40
  41 /* masking of interrupts */
  42 # define _FPU_MASK_ZM  0x10 /* zero divide */
  43 # define _FPU_MASK_OM  0x40 /* overflow */
  44 # define _FPU_MASK_UM  0x20 /* underflow */
  45 # define _FPU_MASK_XM  0x08 /* inexact */
  46 # define _FPU_MASK_IM  0x80 /* invalid operation */
  47
  48 # define _FPU_RESERVED 0xffffff00 /* These bits are reserved are not changed. */
  49
  50 /* The fdlibm code requires no interrupts for exceptions.  */
  51 # define _FPU_DEFAULT  0x00000000 /* Default value.  */
  52
  53 /* IEEE:  same as above, but (some) exceptions;
  54    we leave the 'inexact' exception off.
  55  */
  56 # define _FPU_IEEE     0x000000f0
  57
  58 /* Type of the control word.  */
  59 typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__)));
  60
  61 /* Macros for accessing the hardware control word.  */
  62 # define _FPU_GETCW(__cw) ( { \
  63   union { double d; fpu_control_t cw[2]; } \
  64     tmp __attribute__ ((__aligned__(8))); \
  65   __asm__ ("mffs 0; stfd%U0 0,%0" : "=m" (tmp.d) : : "fr0"); \
  66   (__cw)=tmp.cw[1]; \
  67   tmp.cw[1]; } )
  68 # define _FPU_SETCW(__cw) { \
  69   union { double d; fpu_control_t cw[2]; } \
  70     tmp __attribute__ ((__aligned__(8))); \
  71   tmp.cw[0] = 0xFFF80000; /* More-or-less arbitrary; this is a QNaN. */ \
  72   tmp.cw[1] = __cw; \
  73   __asm__ ("lfd%U0 0,%0; mtfsf 255,0" : : "m" (tmp.d) : "fr0"); \
  74 }
  75
  76 /* Default control word set at startup.  */
  77 extern fpu_control_t __fpu_control;
  78
  79 #endif /* PowerPC 6xx floating-point.  */
  80
  81 #endif /* _FPU_CONTROL_H */