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authorMike Frysinger <vapier@gentoo.org>2005-11-03 23:57:25 +0000
committerMike Frysinger <vapier@gentoo.org>2005-11-03 23:57:25 +0000
commitea8e9b58cc284de51f163abf762c0504880a4041 (patch)
treef296281888098f7a6bed1eb0dfe46424c6535847 /libm/s_lround.c
parentabc27c85d619d917d411080a24373f98fe5d88ac (diff)
add implementations from glibc for the round functions
Diffstat (limited to 'libm/s_lround.c')
-rw-r--r--libm/s_lround.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/libm/s_lround.c b/libm/s_lround.c
new file mode 100644
index 000000000..5b1d5467e
--- /dev/null
+++ b/libm/s_lround.c
@@ -0,0 +1,75 @@
+/* Round double value to long int.
+ Copyright (C) 1997, 2004 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"
+
+
+long int
+lround (double x)
+{
+ int32_t j0;
+ u_int32_t i1, i0;
+ long int result;
+ int sign;
+
+ EXTRACT_WORDS (i0, i1, x);
+ j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+ sign = (i0 & 0x80000000) != 0 ? -1 : 1;
+ i0 &= 0xfffff;
+ i0 |= 0x100000;
+
+ if (j0 < 20)
+ {
+ if (j0 < 0)
+ return j0 < -1 ? 0 : sign;
+ else
+ {
+ i0 += 0x80000 >> j0;
+
+ result = i0 >> (20 - j0);
+ }
+ }
+ else if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
+ {
+ if (j0 >= 52)
+ result = ((long int) i0 << (j0 - 20)) | (i1 << (j0 - 52));
+ else
+ {
+ u_int32_t j = i1 + (0x80000000 >> (j0 - 20));
+ if (j < i1)
+ ++i0;
+
+ if (j0 == 20)
+ result = (long int) i0;
+ else
+ result = ((long int) i0 << (j0 - 20)) | (j >> (52 - j0));
+ }
+ }
+ else
+ {
+ /* The number is too large. It is left implementation defined
+ what happens. */
+ return (long int) x;
+ }
+
+ return sign * result;
+}