sysdeps/am33/fpu/fpu_control.h

   1 /* FPU control word bits.  AM33/2.0 version.
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2004
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Alexandre Oliva <aoliva@redhat.com>
   6    based on the corresponding file in the mips port.
   7
   8    The GNU C Library is free software; you can redistribute it and/or
   9    modify it under the terms of the GNU Lesser General Public
  10    License as published by the Free Software Foundation; either
  11    version 2.1 of the License, or (at your option) any later version.
  12
  13    The GNU C Library is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16    Lesser General Public License for more details.
  17
  18    You should have received a copy of the GNU Lesser General Public
  19    License along with the GNU C Library; if not, write to the Free
  20    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  21    02111-1307 USA.  */
  22
  23 #ifndef _FPU_CONTROL_H
  24 #define _FPU_CONTROL_H
  25
  26 /* AM33/2.0 FPU floating point control register bits.
  27  *
  28  * 31-22  -> reserved
  29  * 21-18  -> floating-point condition codes (L, G, E, U)
  30  * 17-16  -> rounding modes (00 is to-nearest; other values are reserved
  31  * 15     -> reserved (read as 0, write with 0)
  32  * 14-10  -> Exception Cause (inValid, divZero, Overflow, Underflow, Inexact)
  33  *  9- 5  -> Exception Enable
  34  *  4- 0  -> Exception Flag, cleared when exception cause is set
  35  */
  36
  37 #include <features.h>
  38 #include <fenv.h>
  39
  40 /* masking of interrupts */
  41 #define _FPU_MASK_V     0x0200  /* Invalid operation */
  42 #define _FPU_MASK_Z     0x0100  /* Division by zero  */
  43 #define _FPU_MASK_O     0x0080  /* Overflow          */
  44 #define _FPU_MASK_U     0x0040  /* Underflow         */
  45 #define _FPU_MASK_I     0x0020  /* Inexact operation */
  46
  47 /* rounding control */
  48 #define _FPU_RC_NEAREST 0x0     /* Only available mode */
  49
  50 #define _FPU_RESERVED 0xffc08000  /* Reserved bits in fpcr */
  51
  52
  53 /* The fdlibm code requires strict IEEE double precision arithmetic,
  54    and no interrupts for exceptions, rounding to nearest.  */
  55
  56 #define _FPU_DEFAULT  0x0000001f
  57
  58 /* IEEE:  same as above, but exceptions */
  59 #define _FPU_IEEE     0x000003ff
  60
  61 /* Type of the control word.  */
  62 typedef unsigned int fpu_control_t;
  63
  64 /* Macros for accessing the hardware control word.  _FPU_SETCW is
  65    defined such that it won't modify the EF bits, that are cleared
  66    when assigned bits that are set.  Use SETFCW to get them actually
  67    reset.  */
  68 #define _FPU_SETFCW(cw) __asm__ ("fmov %0,fpcr" : : "ri" (cw))
  69 #define _FPU_SETCW(cw) _FPU_SETFCW((cw) & ~FE_ALL_EXCEPT)
  70 #define _FPU_GETCW(cw) __asm__ ("fmov fpcr,%0" : "=r" (cw))
  71
  72 /* Default control word set at startup.  */
  73 extern fpu_control_t __fpu_control;
  74
  75 #endif  /* fpu_control.h */