ports/sysdeps/hppa/fpu/fraiseexcpt.c

   1 /* Raise given exceptions.
   2    Copyright (C) 1997-2014 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, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <fenv.h>
  21 #include <float.h>
  22 #include <math.h>
  23
  24 /* Please see section 10,
  25    page 10-5 "Delayed Trapping" in the PA-RISC 2.0 Architecture manual */
  26
  27 int
  28 feraiseexcept (int excepts)
  29 {
  30   /* Raise exceptions represented by EXCEPTS.  But we must raise only one
  31      signal at a time.  It is important that if the overflow/underflow
  32      exception and the divide by zero exception are given at the same
  33      time, the overflow/underflow exception follows the divide by zero
  34      exception.  */
  35
  36   /* We do these bits in assembly to be certain GCC doesn't optimize
  37      away something important, and so we can force delayed traps to
  38      occur. */
  39
  40   /* We use "fldd 0(%%sr0,%%sp),%0" to flush the delayed exception */
  41
  42   /* First: Invalid exception.  */
  43   if (excepts & FE_INVALID)
  44     {
  45       /* One example of an invalid operation is 0 * Infinity.  */
  46       double d = HUGE_VAL;
  47       __asm__ __volatile__ (
  48                 "       fcpy,dbl %%fr0,%%fr22\n"
  49                 "       fmpy,dbl %0,%%fr22,%0\n"
  50                 "       fldd 0(%%sr0,%%sp),%0"
  51                 : "+f" (d) : : "%fr22" );
  52     }
  53
  54   /* Second: Division by zero.  */
  55   if (excepts & FE_DIVBYZERO)
  56     {
  57       double d = 1.0;
  58       __asm__ __volatile__ (
  59                 "       fcpy,dbl %%fr0,%%fr22\n"
  60                 "       fdiv,dbl %0,%%fr22,%0\n"
  61                 "       fldd 0(%%sr0,%%sp),%0"
  62                 : "+f" (d) : : "%fr22" );
  63     }
  64
  65   /* Third: Overflow.  */
  66   if (excepts & FE_OVERFLOW)
  67     {
  68       double d = DBL_MAX;
  69       __asm__ __volatile__ (
  70                 "       fadd,dbl %0,%0,%0\n"
  71                 "       fldd 0(%%sr0,%%sp),%0"
  72                 : "+f" (d) );
  73     }
  74
  75   /* Fourth: Underflow.  */
  76   if (excepts & FE_UNDERFLOW)
  77     {
  78       double d = DBL_MIN;
  79       double e = 3.0;
  80       __asm__ __volatile__ (
  81                 "       fdiv,dbl %0,%1,%0\n"
  82                 "       fldd 0(%%sr0,%%sp),%0"
  83                 : "+f" (d) : "f" (e) );
  84     }
  85
  86   /* Fifth: Inexact */
  87   if (excepts & FE_INEXACT)
  88     {
  89       double d = M_PI;
  90       double e = 69.69;
  91       __asm__ __volatile__ (
  92                 "       fdiv,dbl %0,%1,%%fr22\n"
  93                 "       fcnvfxt,dbl,sgl %%fr22,%%fr22L\n"
  94                 "       fldd 0(%%sr0,%%sp),%%fr22"
  95                 : : "f" (d), "f" (e) : "%fr22" );
  96     }
  97
  98   /* Success.  */
  99   return 0;
 100 }
 101 libm_hidden_def (feraiseexcept)