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sfp-exceptions.c revision 1.1.1.9 
      1 /*
      2  * Copyright (C) 2012-2020 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       asm volatile ("%vdivss\t{%0, %d0|%d0, %0}" : "+x" (f));
     52 #else
     53       asm volatile ("fdiv\t{%y0, %0|%0, %y0}" : "+t" (f));
     54       /* No need for fwait, exception is triggered by emitted fstp.  */
     55 #endif
     56     }
     57   if (_fex & FP_EX_DENORM)
     58     {
     59       struct fenv temp;
     60       asm volatile ("fnstenv\t%0" : "=m" (temp));
     61       temp.__status_word |= FP_EX_DENORM;
     62       asm volatile ("fldenv\t%0" : : "m" (temp));
     63       asm volatile ("fwait");
     64     }
     65   if (_fex & FP_EX_DIVZERO)
     66     {
     67       float f = 1.0f, g = 0.0f;
     68 #ifdef __SSE_MATH__
     69       asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
     70 #else
     71       asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
     72       /* No need for fwait, exception is triggered by emitted fstp.  */
     73 #endif
     74     }
     75   if (_fex & FP_EX_OVERFLOW)
     76     {
     77       struct fenv temp;
     78       asm volatile ("fnstenv\t%0" : "=m" (temp));
     79       temp.__status_word |= FP_EX_OVERFLOW;
     80       asm volatile ("fldenv\t%0" : : "m" (temp));
     81       asm volatile ("fwait");
     82     }
     83   if (_fex & FP_EX_UNDERFLOW)
     84     {
     85       struct fenv temp;
     86       asm volatile ("fnstenv\t%0" : "=m" (temp));
     87       temp.__status_word |= FP_EX_UNDERFLOW;
     88       asm volatile ("fldenv\t%0" : : "m" (temp));
     89       asm volatile ("fwait");
     90     }
     91   if (_fex & FP_EX_INEXACT)
     92     {
     93       float f = 1.0f, g = 3.0f;
     94 #ifdef __SSE_MATH__
     95       asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
     96 #else
     97       asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
     98       /* No need for fwait, exception is triggered by emitted fstp.  */
     99 #endif
    100     }
    101 }
    102 #endif
    103