libgcc/sfp-exceptions.c

   1 /*
   2  * Copyright (C) 2012-2017 Free Software Foundation, Inc.
   3  *
   4  * This file is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the
   6  * Free Software Foundation; either version 3, or (at your option) any
   7  * later version.
   8  *
   9  * This file is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * Under Section 7 of GPL version 3, you are granted additional
  15  * permissions described in the GCC Runtime Library Exception, version
  16  * 3.1, as published by the Free Software Foundation.
  17  *
  18  * You should have received a copy of the GNU General Public License and
  19  * a copy of the GCC Runtime Library Exception along with this program;
  20  * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  21  * <http://www.gnu.org/licenses/>.
  22  */
  23
  24 #ifndef _SOFT_FLOAT
  25 #include "sfp-machine.h"
  26
  27 struct fenv
  28 {
  29   unsigned short int __control_word;
  30   unsigned short int __unused1;
  31   unsigned short int __status_word;
  32   unsigned short int __unused2;
  33   unsigned short int __tags;
  34   unsigned short int __unused3;
  35   unsigned int __eip;
  36   unsigned short int __cs_selector;
  37   unsigned int __opcode:11;
  38   unsigned int __unused4:5;
  39   unsigned int __data_offset;
  40   unsigned short int __data_selector;
  41   unsigned short int __unused5;
  42 };
  43
  44 void
  45 __sfp_handle_exceptions (int _fex)
  46 {
  47   if (_fex & FP_EX_INVALID)
  48     {
  49       float f = 0.0f;
  50 #ifdef __SSE_MATH__
  51       volatile float r __attribute__ ((unused));
  52       asm volatile ("%vdivss\t{%0, %d0|%d0, %0}" : "+x" (f));
  53       r = f; /* Needed to trigger exception.   */
  54 #else
  55       asm volatile ("fdiv\t{%y0, %0|%0, %y0}" : "+t" (f));
  56       /* No need for fwait, exception is triggered by emitted fstp.  */
  57 #endif
  58     }
  59   if (_fex & FP_EX_DENORM)
  60     {
  61       struct fenv temp;
  62       asm volatile ("fnstenv\t%0" : "=m" (temp));
  63       temp.__status_word |= FP_EX_DENORM;
  64       asm volatile ("fldenv\t%0" : : "m" (temp));
  65       asm volatile ("fwait");
  66     }
  67   if (_fex & FP_EX_DIVZERO)
  68     {
  69       float f = 1.0f, g = 0.0f;
  70 #ifdef __SSE_MATH__
  71       volatile float r __attribute__ ((unused));
  72       asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
  73       r = f; /* Needed to trigger exception.   */
  74 #else
  75       asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
  76       /* No need for fwait, exception is triggered by emitted fstp.  */
  77 #endif
  78     }
  79   if (_fex & FP_EX_OVERFLOW)
  80     {
  81       struct fenv temp;
  82       asm volatile ("fnstenv\t%0" : "=m" (temp));
  83       temp.__status_word |= FP_EX_OVERFLOW;
  84       asm volatile ("fldenv\t%0" : : "m" (temp));
  85       asm volatile ("fwait");
  86     }
  87   if (_fex & FP_EX_UNDERFLOW)
  88     {
  89       struct fenv temp;
  90       asm volatile ("fnstenv\t%0" : "=m" (temp));
  91       temp.__status_word |= FP_EX_UNDERFLOW;
  92       asm volatile ("fldenv\t%0" : : "m" (temp));
  93       asm volatile ("fwait");
  94     }
  95   if (_fex & FP_EX_INEXACT)
  96     {
  97       float f = 1.0f, g = 3.0f;
  98 #ifdef __SSE_MATH__
  99       volatile float r __attribute__ ((unused));
 100       asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
 101       r = f; /* Needed to trigger exception.   */
 102 #else
 103       asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
 104       /* No need for fwait, exception is triggered by emitted fstp.  */
 105 #endif
 106     }
 107 };
 108 #endif