sysdeps/aarch64/fpu/fraiseexcpt.c

   1 /* Copyright (C) 1997-2017 Free Software Foundation, Inc.
   2
   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 License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    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 <fpu_control.h>
  21 #include <float.h>
  22
  23 int
  24 __feraiseexcept (int excepts)
  25 {
  26   int fpsr;
  27   const float fp_zero = 0.0;
  28   const float fp_one = 1.0;
  29   const float fp_max = FLT_MAX;
  30   const float fp_min = FLT_MIN;
  31   const float fp_1e32 = 1.0e32f;
  32   const float fp_two = 2.0;
  33   const float fp_three = 3.0;
  34
  35   /* Raise exceptions represented by EXCEPTS.  But we must raise only
  36      one signal at a time.  It is important that if the OVERFLOW or
  37      UNDERFLOW exception and the inexact exception are given at the
  38      same time, the OVERFLOW or UNDERFLOW exception precedes the
  39      INEXACT exception.
  40
  41      After each exception we read from the FPSR, to force the
  42      exception to be raised immediately.  */
  43
  44   if (FE_INVALID & excepts)
  45     __asm__ __volatile__ (
  46                           "ldr  s0, %1\n\t"
  47                           "fdiv s0, s0, s0\n\t"
  48                           "mrs  %0, fpsr" : "=r" (fpsr)
  49                           : "m" (fp_zero)
  50                           : "d0");
  51
  52   if (FE_DIVBYZERO & excepts)
  53     __asm__ __volatile__ (
  54                           "ldr  s0, %1\n\t"
  55                           "ldr  s1, %2\n\t"
  56                           "fdiv s0, s0, s1\n\t"
  57                           "mrs  %0, fpsr" : "=r" (fpsr)
  58                           : "m" (fp_one), "m" (fp_zero)
  59                           : "d0", "d1");
  60
  61   if (FE_OVERFLOW & excepts)
  62     /* There's no way to raise overflow without also raising inexact.  */
  63     __asm__ __volatile__ (
  64                           "ldr  s0, %1\n\t"
  65                           "ldr  s1, %2\n\t"
  66                           "fadd s0, s0, s1\n\t"
  67                           "mrs  %0, fpsr" : "=r" (fpsr)
  68                           : "m" (fp_max), "m" (fp_1e32)
  69                           : "d0", "d1");
  70
  71   if (FE_UNDERFLOW & excepts)
  72     __asm__ __volatile__ (
  73                           "ldr  s0, %1\n\t"
  74                           "ldr  s1, %2\n\t"
  75                           "fdiv s0, s0, s1\n\t"
  76                           "mrs  %0, fpsr" : "=r" (fpsr)
  77                           : "m" (fp_min), "m" (fp_three)
  78                           : "d0", "d1");
  79
  80   if (FE_INEXACT & excepts)
  81     __asm__ __volatile__ (
  82                           "ldr  s0, %1\n\t"
  83                           "ldr  s1, %2\n\t"
  84                           "fdiv s0, s0, s1\n\t"
  85                           "mrs  %0, fpsr" : "=r" (fpsr)
  86                           : "m" (fp_two), "m" (fp_three)
  87                           : "d0", "d1");
  88
  89   return 0;
  90 }
  91 libm_hidden_def (__feraiseexcept)
  92 weak_alias (__feraiseexcept, feraiseexcept)
  93 libm_hidden_weak (feraiseexcept)