ports/sysdeps/m68k/coldfire/fpu/fraiseexcpt.c

   1 /* Raise given exceptions.
   2    Copyright (C) 2006-2014 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    <http://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)