1  /* Raise given exceptions.
       2     Copyright (C) 2006-2023 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 <float.h>
      21  #include <math.h>
      22  
      23  int
      24  __feraiseexcept (int excepts)
      25  {
      26    /* Raise exceptions represented by EXCEPTS.  But we must raise only one
      27       signal at a time.  It is important that if the overflow/underflow
      28       exception and the divide by zero exception are given at the same
      29       time, the overflow/underflow exception follows the divide by zero
      30       exception.
      31  
      32       The Coldfire FPU allows an exception to be raised by asserting
      33       the associated EXC bit and then executing an arbitrary arithmetic
      34       instruction.  fmove.l is classified as an arithmetic instruction
      35       and suffices for this purpose.
      36  
      37       We therefore raise an exception by setting both the EXC and AEXC
      38       bit associated with the exception (the former being 6 bits to the
      39       left of the latter) and then loading the longword at (%sp) into an
      40       FP register.  */
      41  
      42    inline void
      43    raise_one_exception (int mask)
      44    {
      45      if (excepts & mask)
      46        {
      47  	int fpsr;
      48  	double unused;
      49  
      50  	asm volatile ("fmove%.l %/fpsr,%0" : "=d" (fpsr));
      51  	fpsr |= (mask << 6) | mask;
      52  	asm volatile ("fmove%.l %0,%/fpsr" :: "d" (fpsr));
      53  	asm volatile ("fmove%.l (%%sp),%0" : "=f" (unused));
      54        }
      55    }
      56  
      57    raise_one_exception (FE_INVALID);
      58    raise_one_exception (FE_DIVBYZERO);
      59    raise_one_exception (FE_OVERFLOW);
      60    raise_one_exception (FE_UNDERFLOW);
      61    raise_one_exception (FE_INEXACT);
      62  
      63    /* Success.  */
      64    return 0;
      65  }
      66  libm_hidden_def (__feraiseexcept)
      67  weak_alias (__feraiseexcept, feraiseexcept)
      68  libm_hidden_weak (feraiseexcept)