1  /* Raise given exceptions.
       2     Copyright (C) 2022-2023 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     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <fenv.h>
      20  #include <fpu_control.h>
      21  #include <float.h>
      22  
      23  int
      24  __feraiseexcept (int excepts)
      25  {
      26    const float fp_zero = 0.0f;
      27    const float fp_one = 1.0f;
      28    const float fp_max = FLT_MAX;
      29    const float fp_min = FLT_MIN;
      30    const float fp_1e32 = 1.0e32f;
      31    const float fp_two = 2.0f;
      32    const float fp_three = 3.0f;
      33  
      34    /* Raise exceptions represented by EXPECTS.  But we must raise only
      35       one signal at a time.  It is important that if the overflow/underflow
      36       exception and the inexact exception are given at the same time,
      37       the overflow/underflow exception follows the inexact exception.  */
      38  
      39    /* First: invalid exception.  */
      40    if (FE_INVALID & excepts)
      41      __asm__ __volatile__("fdiv.s $f0,%0,%0\n\t"
      42  			 :
      43  			 : "f"(fp_zero)
      44  			 : "$f0");
      45  
      46    /* Next: division by zero.  */
      47    if (FE_DIVBYZERO & excepts)
      48      __asm__ __volatile__("fdiv.s $f0,%0,%1\n\t"
      49  			 :
      50  			 : "f"(fp_one), "f"(fp_zero)
      51  			 : "$f0");
      52  
      53    /* Next: overflow.  */
      54    if (FE_OVERFLOW & excepts)
      55      /* There's no way to raise overflow without also raising inexact.  */
      56      __asm__ __volatile__("fadd.s $f0,%0,%1\n\t"
      57  			 :
      58  			 : "f"(fp_max), "f"(fp_1e32)
      59  			 : "$f0");
      60  
      61    /* Next: underflow.  */
      62    if (FE_UNDERFLOW & excepts)
      63      __asm__ __volatile__("fdiv.s $f0,%0,%1\n\t"
      64  			 :
      65  			 : "f"(fp_min), "f"(fp_three)
      66  			 : "$f0");
      67  
      68    /* Last: inexact.  */
      69    if (FE_INEXACT & excepts)
      70      __asm__ __volatile__("fdiv.s $f0, %0, %1\n\t"
      71  			 :
      72  			 : "f"(fp_two), "f"(fp_three)
      73  			 : "$f0");
      74  
      75    /* Success.  */
      76    return 0;
      77  }
      78  
      79  libm_hidden_def (__feraiseexcept) weak_alias (__feraiseexcept, feraiseexcept)
      80  libm_hidden_weak (feraiseexcept)