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authorUlrich Drepper <drepper@gmail.com>2011-10-15 21:44:45 -0400
committerUlrich Drepper <drepper@gmail.com>2011-10-15 21:44:45 -0400
commitd4a285692ae21debd4518a6d4980fa7e36d104b5 (patch)
tree9c68d5e87b76a23a72bd800471f0d4ff651eba32 /sysdeps/ieee754/dbl-64/wordsize-64
parentb61099b50a028d3ac69aa9500ffa9871d23e3884 (diff)
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Optimized floor for 64-bit architectures
Diffstat (limited to 'sysdeps/ieee754/dbl-64/wordsize-64')
-rw-r--r--sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c79
1 files changed, 79 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c
new file mode 100644
index 0000000000..d52e4dbeb7
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+++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c
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+/* Round double to integer away from zero.
+ Copyright (C) 2011 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 2011.
+
+ 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. */
+
+/* Based on a version which carries the following copyright: */
+
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+/*
+ * floor(x)
+ * Return x rounded toward -inf to integral value
+ * Method:
+ * Bit twiddling.
+ * Exception:
+ * Inexact flag raised if x not equal to floor(x).
+ */
+
+static const double huge = 1.0e300;
+
+
+double
+__floor (double x)
+{
+ int64_t i0;
+ EXTRACT_WORDS64(i0,x);
+ int32_t j0 = ((i0>>52)&0x7ff)-0x3ff;
+ if(__builtin_expect(j0<52, 1)) {
+ if(j0<0) { /* raise inexact if x != 0 */
+ if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
+ if(i0>=0) {i0=0;}
+ else if((i0&0x7fffffffffffffffl)!=0)
+ { i0=0xbff0000000000000l;}
+ }
+ } else {
+ uint64_t i = (0x000fffffffffffffl)>>j0;
+ if((i0&i)==0) return x; /* x is integral */
+ if(huge+x>0.0) { /* raise inexact flag */
+ if(i0<0) i0 += (0x0010000000000000l)>>j0;
+ i0 &= (~i);
+ }
+ }
+ INSERT_WORDS64(x,i0);
+ } else if (j0==0x400)
+ return x+x; /* inf or NaN */
+ return x;
+}
+weak_alias (__floor, floor)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__floor, __floorl)
+weak_alias (__floor, floorl)
+#endif