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authorWaldemar Brodkorb <wbx@uclibc-ng.org>2017-12-03 21:12:34 +0100
committerWaldemar Brodkorb <wbx@uclibc-ng.org>2017-12-03 21:12:34 +0100
commitedce88cfef2f2a62647c2ab9536ca29694fab292 (patch)
tree5cfc13c44a91bb8b983ee137de38e136289db81e /libm/x86_64/fclrexcpt.c
parentc69db851309995c525b3993a10dc13dabdeb7b33 (diff)
x86_64: add fenv support from glibc
Diffstat (limited to 'libm/x86_64/fclrexcpt.c')
-rw-r--r--libm/x86_64/fclrexcpt.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/libm/x86_64/fclrexcpt.c b/libm/x86_64/fclrexcpt.c
new file mode 100644
index 000000000..ddd4d736c
--- /dev/null
+++ b/libm/x86_64/fclrexcpt.c
@@ -0,0 +1,50 @@
+/* Clear given exceptions in current floating-point environment.
+ Copyright (C) 2001-2017 Free Software Foundation, Inc.
+
+ 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
+feclearexcept (int excepts)
+{
+ fenv_t temp;
+ unsigned int mxcsr;
+
+ /* Mask out unsupported bits/exceptions. */
+ excepts &= FE_ALL_EXCEPT;
+
+ /* Bah, we have to clear selected exceptions. Since there is no
+ `fldsw' instruction we have to do it the hard way. */
+ __asm__ ("fnstenv %0" : "=m" (*&temp));
+
+ /* Clear the relevant bits. */
+ temp.__status_word &= excepts ^ FE_ALL_EXCEPT;
+
+ /* Put the new data in effect. */
+ __asm__ ("fldenv %0" : : "m" (*&temp));
+
+ /* And the same procedure for SSE. */
+ __asm__ ("stmxcsr %0" : "=m" (*&mxcsr));
+
+ /* Clear the relevant bits. */
+ mxcsr &= ~excepts;
+
+ /* And put them into effect. */
+ __asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
+
+ /* Success. */
+ return 0;
+}