x86_64: add fenv support from glibc

1 files changed, 41 insertions, 0 deletions

diff --git a/libm/x86_64/feupdateenv.c b/libm/x86_64/feupdateenv.c
new file mode 100644
index 000000000..83747ea52
--- /dev/null
+++ b/libm/x86_64/feupdateenv.c
@@ -0,0 +1,41 @@
+/* Install given floating-point environment and raise exceptions.
+   Copyright (C) 1997-2017 Free Software Foundation, Inc.
+   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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+
+int
+feupdateenv (const fenv_t *envp)
+{
+  fexcept_t temp;
+  unsigned int xtemp;
+
+  /* Save current exceptions.  */
+  __asm__ ("fnstsw %0\n\tstmxcsr %1" : "=m" (*&temp), "=m" (xtemp));
+  temp = (temp | xtemp) & FE_ALL_EXCEPT;
+
+  /* Install new environment.  */
+  fesetenv (envp);
+
+  /* Raise the saved exception.  Incidently for us the implementation
+     defined format of the values in objects of type fexcept_t is the
+     same as the ones specified using the FE_* constants.  */
+  feraiseexcept ((int) temp);
+
+  /* Success.  */
+  return 0;
+}