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

  for i386. UCLIBC_HAS_FENV

1 files changed, 55 insertions, 0 deletions

diff --git a/libm/i386/feenablxcpt.c b/libm/i386/feenablxcpt.c
new file mode 100644
index 000000000..174f9f1ad
--- /dev/null
+++ b/libm/i386/feenablxcpt.c
@@ -0,0 +1,55 @@
+/* Enable floating-point exceptions.
+   Copyright (C) 1999, 2000, 2003, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Andreas Jaeger <aj@suse.de>, 1999.
+
+   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 <unistd.h>
+
+int
+feenableexcept (int excepts)
+{
+  unsigned short int new_exc;
+  unsigned short int old_exc;
+
+  /* Get the current control word.  */
+  __asm__ ("fstcw %0" : "=m" (*&new_exc));
+
+  excepts &= FE_ALL_EXCEPT;
+  old_exc = (~new_exc) & FE_ALL_EXCEPT;
+
+  new_exc &= ~excepts;
+  __asm__ ("fldcw %0" : : "m" (*&new_exc));
+
+#if 0
+  /* If the CPU supports SSE we set the MXCSR as well.  */
+  if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
+    {
+      unsigned int xnew_exc;
+
+      /* Get the current control word.  */
+      __asm__ ("stmxcsr %0" : "=m" (*&xnew_exc));
+
+      xnew_exc &= ~(excepts << 7);
+
+      __asm__ ("ldmxcsr %0" : : "m" (*&xnew_exc));
+    }
+#endif
+
+  return old_exc;
+}