sysdeps/hppa/fpu/fraiseexcpt.c

   1 /* Raise given exceptions.
   2    Copyright (C) 1997, 1999, 2000, 2002 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by David Huggins-Daines <dhd@debian.org>
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <fenv.h>
  22 #include <float.h>
  23 #include <math.h>
  24
  25 /* Please see section 10,
  26    page 10-5 "Delayed Trapping" in the PA-RISC 2.0 Architecture manual */
  27
  28 int
  29 feraiseexcept (int excepts)
  30 {
  31   /* Raise exceptions represented by EXCEPTS.  But we must raise only one
  32      signal at a time.  It is important that if the overflow/underflow
  33      exception and the divide by zero exception are given at the same
  34      time, the overflow/underflow exception follows the divide by zero
  35      exception.  */
  36
  37   /* We do these bits in assembly to be certain GCC doesn't optimize
  38      away something important, and so we can force delayed traps to
  39      occur. */
  40
  41   /* We use "fldd 0(%%sr0,%%sp),%0" to flush the delayed exception */
  42
  43   /* First: Invalid exception.  */
  44   if (excepts & FE_INVALID)
  45     {
  46       /* One example of a invalid operation is 0 * Infinity.  */
  47       double d = HUGE_VAL;
  48       __asm__ __volatile__ (
  49                 "       fcpy,dbl %%fr0,%%fr22\n"
  50                 "       fmpy,dbl %0,%%fr22,%0\n"
  51                 "       fldd 0(%%sr0,%%sp),%0"
  52                 : "+f" (d) : : "%fr22" );
  53     }
  54
  55   /* Second: Division by zero.  */
  56   if (excepts & FE_DIVBYZERO)
  57     {
  58       double d = 1.0;
  59       __asm__ __volatile__ (
  60                 "       fcpy,dbl %%fr0,%%fr22\n"
  61                 "       fdiv,dbl %0,%%fr22,%0\n"
  62                 "       fldd 0(%%sr0,%%sp),%0"
  63                 : "+f" (d) : : "%fr22" );
  64     }
  65
  66   /* Third: Overflow.  */
  67   if (excepts & FE_OVERFLOW)
  68     {
  69       double d = DBL_MAX;
  70       __asm__ __volatile__ (
  71                 "       fadd,dbl %0,%0,%0\n"
  72                 "       fldd 0(%%sr0,%%sp),%0"
  73                 : "+f" (d) );
  74     }
  75
  76   /* Fourth: Underflow.  */
  77   if (excepts & FE_UNDERFLOW)
  78     {
  79       double d = DBL_MIN;
  80       double e = 3.0;
  81       __asm__ __volatile__ (
  82                 "       fdiv,dbl %0,%1,%0\n"
  83                 "       fldd 0(%%sr0,%%sp),%0"
  84                 : "+f" (d) : "f" (e) );
  85     }
  86
  87   /* Fifth: Inexact */
  88   if (excepts & FE_INEXACT)
  89     {
  90       double d = M_PI;
  91       double e = 69.69;
  92       __asm__ __volatile__ (
  93                 "       fdiv,dbl %0,%1,%%fr22\n"
  94                 "       fcnvfxt,dbl,sgl %%fr22,%%fr22L\n"
  95                 "       fldd 0(%%sr0,%%sp),%%fr22"
  96                 : : "f" (d), "f" (e) : "%fr22" );
  97     }
  98
  99   /* Success.  */
 100   return 0;
 101 }
 102 libm_hidden_def (feraiseexcept)