summaryrefslogtreecommitdiff
path: root/libm/x86_64/feholdexcpt.c
diff options
context:
space:
mode:
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/feholdexcpt.c
parentc69db851309995c525b3993a10dc13dabdeb7b33 (diff)
x86_64: add fenv support from glibc
Diffstat (limited to 'libm/x86_64/feholdexcpt.c')
-rw-r--r--libm/x86_64/feholdexcpt.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/libm/x86_64/feholdexcpt.c b/libm/x86_64/feholdexcpt.c
new file mode 100644
index 000000000..917e5f84b
--- /dev/null
+++ b/libm/x86_64/feholdexcpt.c
@@ -0,0 +1,37 @@
+/* Store current floating-point environment and clear exceptions.
+ 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
+feholdexcept (fenv_t *envp)
+{
+ unsigned int mxcsr;
+
+ /* Store the environment. Recall that fnstenv has a side effect of
+ masking all exceptions. Then clear all exceptions. */
+ __asm__ ("fnstenv %0\n\t"
+ "stmxcsr %1\n\t"
+ "fnclex"
+ : "=m" (*envp), "=m" (envp->__mxcsr));
+
+ /* Set the SSE MXCSR register. */
+ mxcsr = (envp->__mxcsr | 0x1f80) & ~0x3f;
+ __asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
+
+ return 0;
+}