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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/fraiseexcpt.c
parentc69db851309995c525b3993a10dc13dabdeb7b33 (diff)
x86_64: add fenv support from glibc
Diffstat (limited to 'libm/x86_64/fraiseexcpt.c')
-rw-r--r--libm/x86_64/fraiseexcpt.c117
1 files changed, 117 insertions, 0 deletions
diff --git a/libm/x86_64/fraiseexcpt.c b/libm/x86_64/fraiseexcpt.c
new file mode 100644
index 000000000..524c02a41
--- /dev/null
+++ b/libm/x86_64/fraiseexcpt.c
@@ -0,0 +1,117 @@
+/* Raise given 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>
+#include <math.h>
+
+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 an invalid operation is 0.0 / 0.0. */
+ float f = 0.0;
+
+ __asm__ __volatile__ ("divss %0, %0 " : : "x" (f));
+ (void) &f;
+ }
+
+ /* Next: division by zero. */
+ if ((FE_DIVBYZERO & excepts) != 0)
+ {
+ float f = 1.0;
+ float g = 0.0;
+
+ __asm__ __volatile__ ("divss %1, %0" : : "x" (f), "x" (g));
+ (void) &f;
+ }
+
+ /* Next: overflow. */
+ if ((FE_OVERFLOW & excepts) != 0)
+ {
+ /* XXX: Is it ok to only set the x87 FPU? */
+ /* 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)
+ {
+ /* XXX: Is it ok to only set the x87 FPU? */
+ /* 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)
+ {
+ /* XXX: Is it ok to only set the x87 FPU? */
+ /* 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;
+}