- add C99 floating point environment, rounding and exception handling functions

  for i386. UCLIBC_HAS_FENV

1 files changed, 118 insertions, 0 deletions

diff --git a/libm/i386/fraiseexcpt.c b/libm/i386/fraiseexcpt.c
new file mode 100644
index 000000000..fcb3d0e84
--- /dev/null
+++ b/libm/i386/fraiseexcpt.c
@@ -0,0 +1,118 @@
+/* Raise given exceptions.
+   Copyright (C) 1997,99,2000,01,02 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <fenv.h>
+#include <math.h>
+
+libm_hidden_proto(feraiseexcept)
+
+int
+feraiseexcept (int excepts)
+{
+  /* Raise exceptions represented by EXPECTS.  But we must raise only
+     one signal at a time.  It is important that if the overflow/underflow
+     exception and the inexact exception are given at the same time,
+     the overflow/underflow exception follows the inexact exception.  */
+
+  /* First: invalid exception.  */
+  if ((FE_INVALID & excepts) != 0)
+    {
+      /* One example of a invalid operation is 0.0 / 0.0.  */
+      double d;
+      __asm__ __volatile__ ("fldz; fdiv %%st, %%st(0); fwait" : "=t" (d));
+      (void) &d;
+    }
+
+  /* Next: division by zero.  */
+  if ((FE_DIVBYZERO & excepts) != 0)
+    {
+      double d;
+      __asm__ __volatile__ ("fldz; fld1; fdivp %%st, %%st(1); fwait"
+			    : "=t" (d));
+      (void) &d;
+    }
+
+  /* Next: overflow.  */
+  if ((FE_OVERFLOW & excepts) != 0)
+    {
+      /* There is no way to raise only the overflow flag.  Do it the
+	 hard way.  */
+      fenv_t temp;
+
+      /* Bah, we have to clear selected exceptions.  Since there is no
+	 `fldsw' instruction we have to do it the hard way.  */
+      __asm__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
+
+      /* Set the relevant bits.  */
+      temp.__status_word |= FE_OVERFLOW;
+
+      /* Put the new data in effect.  */
+      __asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
+
+      /* And raise the exception.  */
+      __asm__ __volatile__ ("fwait");
+    }
+
+  /* Next: underflow.  */
+  if ((FE_UNDERFLOW & excepts) != 0)
+    {
+      /* There is no way to raise only the underflow flag.  Do it the
+	 hard way.  */
+      fenv_t temp;
+
+      /* Bah, we have to clear selected exceptions.  Since there is no
+	 `fldsw' instruction we have to do it the hard way.  */
+      __asm__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
+
+      /* Set the relevant bits.  */
+      temp.__status_word |= FE_UNDERFLOW;
+
+      /* Put the new data in effect.  */
+      __asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
+
+      /* And raise the exception.  */
+      __asm__ __volatile__ ("fwait");
+    }
+
+  /* Last: inexact.  */
+  if ((FE_INEXACT & excepts) != 0)
+    {
+      /* There is no way to raise only the inexact flag.  Do it the
+	 hard way.  */
+      fenv_t temp;
+
+      /* Bah, we have to clear selected exceptions.  Since there is no
+	 `fldsw' instruction we have to do it the hard way.  */
+      __asm__ __volatile__ ("fnstenv %0" : "=m" (*&temp));
+
+      /* Set the relevant bits.  */
+      temp.__status_word |= FE_INEXACT;
+
+      /* Put the new data in effect.  */
+      __asm__ __volatile__ ("fldenv %0" : : "m" (*&temp));
+
+      /* And raise the exception.  */
+      __asm__ __volatile__ ("fwait");
+    }
+
+  /* Success.  */
+  return 0;
+}
+libm_hidden_def(feraiseexcept)