sysdeps/powerpc/fpu_control.h

   1 /* FPU control word definitions.  PowerPC version.
   2    Copyright (C) 1996-2017 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 #ifdef _SOFT_FLOAT
  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 #elif defined __NO_FPRS__ /* e500 */
  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 /* masking of interrupts */
  40 # define _FPU_MASK_ZM  0x10 /* zero divide */
  41 # define _FPU_MASK_OM  0x04 /* overflow */
  42 # define _FPU_MASK_UM  0x08 /* underflow */
  43 # define _FPU_MASK_XM  0x40 /* inexact */
  44 # define _FPU_MASK_IM  0x20 /* invalid operation */
  45
  46 # define _FPU_RESERVED 0x00c10080 /* These bits are reserved and not changed. */
  47
  48 /* Correct IEEE semantics require traps to be enabled at the hardware
  49    level; the kernel then does the emulation and determines whether
  50    generation of signals from those traps was enabled using prctl.  */
  51 # define _FPU_DEFAULT  0x0000003c /* Default value.  */
  52 # define _FPU_IEEE     _FPU_DEFAULT
  53
  54 /* Type of the control word.  */
  55 typedef unsigned int fpu_control_t;
  56
  57 /* Macros for accessing the hardware control word.  */
  58 # define _FPU_GETCW(cw) \
  59   __asm__ volatile ("mfspefscr %0" : "=r" (cw))
  60 # define _FPU_SETCW(cw) \
  61   __asm__ volatile ("mtspefscr %0" : : "r" (cw))
  62
  63 /* Default control word set at startup.  */
  64 extern fpu_control_t __fpu_control;
  65
  66 #else /* PowerPC 6xx floating-point.  */
  67
  68 /* rounding control */
  69 # define _FPU_RC_NEAREST 0x00   /* RECOMMENDED */
  70 # define _FPU_RC_DOWN    0x03
  71 # define _FPU_RC_UP      0x02
  72 # define _FPU_RC_ZERO    0x01
  73
  74 # define _FPU_MASK_NI  0x04 /* non-ieee mode */
  75
  76 /* masking of interrupts */
  77 # define _FPU_MASK_ZM  0x10 /* zero divide */
  78 # define _FPU_MASK_OM  0x40 /* overflow */
  79 # define _FPU_MASK_UM  0x20 /* underflow */
  80 # define _FPU_MASK_XM  0x08 /* inexact */
  81 # define _FPU_MASK_IM  0x80 /* invalid operation */
  82
  83 # define _FPU_RESERVED 0xffffff00 /* These bits are reserved are not changed. */
  84
  85 /* The fdlibm code requires no interrupts for exceptions.  */
  86 # define _FPU_DEFAULT  0x00000000 /* Default value.  */
  87
  88 /* IEEE:  same as above, but (some) exceptions;
  89    we leave the 'inexact' exception off.
  90  */
  91 # define _FPU_IEEE     0x000000f0
  92
  93 /* Type of the control word.  */
  94 typedef unsigned int fpu_control_t;
  95
  96 /* Macros for accessing the hardware control word.  */
  97 # define _FPU_GETCW(cw)                                         \
  98   ({union { double __d; unsigned long long __ll; } __u;         \
  99     register double __fr;                                       \
 100     __asm__ ("mffs %0" : "=f" (__fr));                          \
 101     __u.__d = __fr;                                             \
 102     (cw) = (fpu_control_t) __u.__ll;                            \
 103     (fpu_control_t) __u.__ll;                                   \
 104   })
 105
 106 # define _FPU_SETCW(cw)                                         \
 107   { union { double __d; unsigned long long __ll; } __u;         \
 108     register double __fr;                                       \
 109     __u.__ll = 0xfff80000LL << 32; /* This is a QNaN.  */       \
 110     __u.__ll |= (cw) & 0xffffffffLL;                            \
 111     __fr = __u.__d;                                             \
 112     __asm__ ("mtfsf 255,%0" : : "f" (__fr));                    \
 113   }
 114
 115 /* Default control word set at startup.  */
 116 extern fpu_control_t __fpu_control;
 117
 118 #endif /* PowerPC 6xx floating-point.  */
 119
 120 #endif /* _FPU_CONTROL_H */