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authorBernhard Reutner-Fischer <rep.dot.nop@gmail.com>2008-01-19 15:23:14 +0000
committerBernhard Reutner-Fischer <rep.dot.nop@gmail.com>2008-01-19 15:23:14 +0000
commitbce5bba7a01fb090f67fec5f79218c505c841af3 (patch)
treee7d7dfc12cae1f1474800071fbc4633fa509ef6e /libm/i386/fesetround.c
parentd22976dd5e16e8719abd5c542e17427eeece7ff6 (diff)
- add C99 floating point environment, rounding and exception handling functions
for i386. UCLIBC_HAS_FENV
Diffstat (limited to 'libm/i386/fesetround.c')
-rw-r--r--libm/i386/fesetround.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/libm/i386/fesetround.c b/libm/i386/fesetround.c
new file mode 100644
index 000000000..e1ba16975
--- /dev/null
+++ b/libm/i386/fesetround.c
@@ -0,0 +1,52 @@
+/* Set current rounding direction.
+ Copyright (C) 1997, 2003, 2004, 2005 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <fenv.h>
+#include <unistd.h>
+
+int
+fesetround (int round)
+{
+ unsigned short int cw;
+
+ if ((round & ~0xc00) != 0)
+ /* ROUND is no valid rounding mode. */
+ return 1;
+
+ __asm__ ("fnstcw %0" : "=m" (*&cw));
+ cw &= ~0xc00;
+ cw |= round;
+ __asm__ ("fldcw %0" : : "m" (*&cw));
+
+#if 0
+ /* If the CPU supports SSE we set the MXCSR as well. */
+ if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
+ {
+ unsigned int xcw;
+
+ __asm__ ("stmxcsr %0" : "=m" (*&xcw));
+ xcw &= ~0x6000;
+ xcw |= round << 3;
+ __asm__ ("ldmxcsr %0" : : "m" (*&xcw));
+ }
+#endif
+
+ return 0;
+}