aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/alpha/fpu/s_floorf.c
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/alpha/fpu/s_floorf.c')
-rw-r--r--sysdeps/alpha/fpu/s_floorf.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/sysdeps/alpha/fpu/s_floorf.c b/sysdeps/alpha/fpu/s_floorf.c
new file mode 100644
index 0000000000..fe4c40b929
--- /dev/null
+++ b/sysdeps/alpha/fpu/s_floorf.c
@@ -0,0 +1,55 @@
+/* Copyright (C) 1998-2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Richard Henderson.
+
+ 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 <math.h>
+
+
+/* Use the -inf rounding mode conversion instructions to implement
+ floor. We note when the exponent is large enough that the value
+ must be integral, as this avoids unpleasant integer overflows. */
+
+float
+__floorf (float x)
+{
+ if (isless (fabsf (x), 16777216.0f)) /* 1 << FLT_MANT_DIG */
+ {
+ /* Note that Alpha S_Floating is stored in registers in a
+ restricted T_Floating format, so we don't even need to
+ convert back to S_Floating in the end. The initial
+ conversion to T_Floating is needed to handle denormals. */
+
+ float tmp1, tmp2, new_x;
+
+ __asm ("cvtst/s %3,%2\n\t"
+#ifdef _IEEE_FP_INEXACT
+ "cvttq/svim %2,%1\n\t"
+#else
+ "cvttq/svm %2,%1\n\t"
+#endif
+ "cvtqt/m %1,%0\n\t"
+ : "=f"(new_x), "=&f"(tmp1), "=&f"(tmp2)
+ : "f"(x));
+
+ /* floor(-0) == -0, and in general we'll always have the same
+ sign as our input. */
+ x = copysignf(new_x, x);
+ }
+ return x;
+}
+
+weak_alias (__floorf, floorf)