libgcc/config/i386/sfp-exceptions.c

   1 /*
   2  * Copyright (C) 2012-2024 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 } __attribute__ ((gcc_struct));
  43
  44 #ifdef __SSE_MATH__
  45 # define __math_force_eval_div(x, y) \
  46   do { asm ("" : "+x" (x)); asm volatile ("" : : "x" (x / y)); } while (0)
  47 #else
  48 # define __math_force_eval_div(x, y) \
  49   do { asm ("" : "+t" (x)); asm volatile ("" : : "f" (x / y)); } while (0)
  50 #endif
  51
  52 void
  53 __sfp_handle_exceptions (int _fex)
  54 {
  55   struct fenv temp;
  56
  57   if (_fex & FP_EX_INVALID)
  58     {
  59       float f = 0.0f;
  60       __math_force_eval_div (f, f);
  61     }
  62   if (_fex & FP_EX_DENORM)
  63     {
  64       asm volatile ("fnstenv\t%0" : "=m" (temp));
  65       temp.__status_word |= FP_EX_DENORM;
  66       asm volatile ("fldenv\t%0" : : "m" (temp));
  67       asm volatile ("fwait");
  68     }
  69   if (_fex & FP_EX_DIVZERO)
  70     {
  71       float f = 1.0f, g = 0.0f;
  72       __math_force_eval_div (f, g);
  73     }
  74   if (_fex & FP_EX_OVERFLOW)
  75     {
  76       asm volatile ("fnstenv\t%0" : "=m" (temp));
  77       temp.__status_word |= FP_EX_OVERFLOW;
  78       asm volatile ("fldenv\t%0" : : "m" (temp));
  79       asm volatile ("fwait");
  80     }
  81   if (_fex & FP_EX_UNDERFLOW)
  82     {
  83       asm volatile ("fnstenv\t%0" : "=m" (temp));
  84       temp.__status_word |= FP_EX_UNDERFLOW;
  85       asm volatile ("fldenv\t%0" : : "m" (temp));
  86       asm volatile ("fwait");
  87     }
  88   if (_fex & FP_EX_INEXACT)
  89     {
  90       float f = 1.0f, g = 3.0f;
  91       __math_force_eval_div (f, g);
  92     }
  93 }
  94 #endif