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authorMike Frysinger <vapier@gentoo.org>2007-04-03 01:03:42 +0000
committerMike Frysinger <vapier@gentoo.org>2007-04-03 01:03:42 +0000
commit8334b87bcb31180c70a40ee78e549840fd2d9c0a (patch)
tree3e37ac10d1fc7b7437a30a7bbe83bdcd4bd8c729 /libm/s_llrint.c
parent6ec72c25adc5231d9c12672c8da287db234e55c3 (diff)
import llrint() from glibc
Diffstat (limited to 'libm/s_llrint.c')
-rw-r--r--libm/s_llrint.c93
1 files changed, 93 insertions, 0 deletions
diff --git a/libm/s_llrint.c b/libm/s_llrint.c
new file mode 100644
index 000000000..64c870eaa
--- /dev/null
+++ b/libm/s_llrint.c
@@ -0,0 +1,93 @@
+/* Round argument to nearest integral value according to current rounding
+ direction.
+ Copyright (C) 1997, 2004, 2006 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 <math.h>
+
+#include "math_private.h"
+
+static const double two52[2] =
+{
+ 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
+ -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
+};
+
+
+long long int
+__llrint (double x)
+{
+ int32_t j0;
+ u_int32_t i1, i0;
+ long long int result;
+ volatile double w;
+ double t;
+ int sx;
+
+ EXTRACT_WORDS (i0, i1, x);
+ j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+ sx = i0 >> 31;
+ i0 &= 0xfffff;
+ i0 |= 0x100000;
+
+ if (j0 < 20)
+ {
+ w = two52[sx] + x;
+ t = w - two52[sx];
+ EXTRACT_WORDS (i0, i1, t);
+ j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+ i0 &= 0xfffff;
+ i0 |= 0x100000;
+
+ result = (j0 < 0 ? 0 : i0 >> (20 - j0));
+ }
+ else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
+ {
+ if (j0 >= 52)
+ result = (((long long int) i0 << 32) | i1) << (j0 - 52);
+ else
+ {
+ w = two52[sx] + x;
+ t = w - two52[sx];
+ EXTRACT_WORDS (i0, i1, t);
+ j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+ i0 &= 0xfffff;
+ i0 |= 0x100000;
+
+ if (j0 == 20)
+ result = (long long int) i0;
+ else
+ result = ((long long int) i0 << (j0 - 20)) | (i1 >> (52 - j0));
+ }
+ }
+ else
+ {
+ /* The number is too large. It is left implementation defined
+ what happens. */
+ return (long long int) x;
+ }
+
+ return sx ? -result : result;
+}
+
+weak_alias (__llrint, llrint)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__llrint, __llrintl)
+weak_alias (__llrint, llrintl)
+#endif