sysdeps/unix/sysv/linux/alpha/fraiseexcpt.c

   1 /* Copyright (C) 2004,2006 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library.  If not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <fenv_libc.h>
  19 #include <sysdep.h>
  20 #include <float.h>
  21 #include <kernel-features.h>
  22 #include "kernel_sysinfo.h"
  23
  24
  25 int
  26 __feraiseexcept (int excepts)
  27 {
  28   INTERNAL_SYSCALL_DECL (err);
  29   unsigned long t = excepts;
  30   long r;
  31
  32   r = INTERNAL_SYSCALL (osf_setsysinfo, err, 2, SSI_IEEE_RAISE_EXCEPTION, &t);
  33
  34 #ifndef __ASSUME_IEEE_RAISE_EXCEPTION
  35   if (!INTERNAL_SYSCALL_ERROR_P (r, err))
  36     return 0;
  37
  38   double d;
  39
  40   /* If we got an error from SSI_IEEE_RAISE_EXCEPTION, assume it means that
  41      the system call isn't actually implemented.  Do the best we can.  */
  42
  43   /* Invalid implemented with 0 / 0 -> NaN.  */
  44   if (excepts & FE_INVALID)
  45     __asm__ __volatile__ ("divs/su $f31,$f31,%0; trapb" : "=f"(d) : );
  46
  47   /* Division By Zero implemented with 1 / 0 -> NaN.  */
  48   if (excepts & FE_DIVBYZERO)
  49     __asm__ __volatile__ ("divs/su %1,$f31,%0; trapb" : "=&f"(d) : "f"(1.0f));
  50
  51   /* Overflow and underflow cannot be had all by themselves.  We can
  52      generate them with arithmetic, but we always get INEXACT raised
  53      at the same time.  Prepare to undo.  */
  54   if ((excepts & (FE_OVERFLOW | FE_UNDERFLOW)) && !(excepts & FE_INEXACT))
  55     INTERNAL_SYSCALL (osf_getsysinfo, err, 2, GSI_IEEE_FP_CONTROL, &t);
  56
  57   /* Overflow implemented with FLT_MAX + FLT_MAX -> Inf.  */
  58   if (excepts & FE_OVERFLOW)
  59     __asm__ __volatile__ ("adds/sui %1,%1,%0; trapb"
  60                           : "=&f"(d) : "f"(FLT_MAX));
  61
  62   /* Underflow implemented with FLT_MIN * FLT_MIN -> 0.  */
  63   if (excepts & FE_UNDERFLOW)
  64     __asm__ __volatile__ ("muls/sui %1,%1,%0; trapb"
  65                           : "=&f"(d) : "f"(FLT_MIN));
  66
  67   /* Inexact implemented with (long)0.5 -> 0.  */
  68   if ((excepts & (FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT)) == FE_INEXACT)
  69     __asm__ __volatile__ ("cvttq/svi %1,%0; trapb" : "=&f"(d) : "f"(0.5f));
  70
  71   /* If we raised inexact when not asked, and inexact was not previously
  72      raised, then clear that exception.  */
  73   if ((excepts & (FE_OVERFLOW | FE_UNDERFLOW))
  74       && !((excepts | t) & FE_INEXACT))
  75     {
  76       t |= excepts & SWCR_STATUS_MASK;
  77       INTERNAL_SYSCALL (osf_setsysinfo, err, 2, SSI_IEEE_FP_CONTROL, &t);
  78     }
  79 #endif /* !__ASSUME_IEEE_RAISE_EXCEPTION */
  80
  81   return 0;
  82 }
  83
  84 #include <shlib-compat.h>
  85 #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
  86 strong_alias (__feraiseexcept, __old_feraiseexcept)
  87 compat_symbol (libm, __old_feraiseexcept, feraiseexcept, GLIBC_2_1);
  88 #endif
  89
  90 libm_hidden_ver (__feraiseexcept, feraiseexcept)
  91 versioned_symbol (libm, __feraiseexcept, feraiseexcept, GLIBC_2_2);