summaryrefslogtreecommitdiff
path: root/libm/s_lrint.c
diff options
context:
space:
mode:
authorMike Frysinger <vapier@gentoo.org>2006-09-23 04:05:33 +0000
committerMike Frysinger <vapier@gentoo.org>2006-09-23 04:05:33 +0000
commita8d3a36f81e3f1e59b40b589dbfbc2044786c953 (patch)
tree1d0fedc9cceb5a6e71cd37d2d004c5b373168e93 /libm/s_lrint.c
parent125208e9cd79a655a5770679143d0f0d85459ad9 (diff)
grab s_lrint from glibc for C99
Diffstat (limited to 'libm/s_lrint.c')
-rw-r--r--libm/s_lrint.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/libm/s_lrint.c b/libm/s_lrint.c
new file mode 100644
index 000000000..61c521240
--- /dev/null
+++ b/libm/s_lrint.c
@@ -0,0 +1,94 @@
+/* Round argument to nearest integral value according to current rounding
+ direction.
+ 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"
+
+static const double two52[2] =
+{
+ 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
+ -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
+};
+
+
+libm_hidden_proto(lrint)
+long int
+lrint (double x)
+{
+ int32_t j0;
+ u_int32_t i0,i1;
+ volatile double w;
+ double t;
+ long int result;
+ int sx;
+
+ EXTRACT_WORDS (i0, i1, x);
+ j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+ sx = i0 >> 31;
+ i0 &= 0xfffff;
+ i0 |= 0x100000;
+
+ if (j0 < 20)
+ {
+ if (j0 < -1)
+ return 0;
+ else
+ {
+ w = two52[sx] + x;
+ t = w - two52[sx];
+ EXTRACT_WORDS (i0, i1, t);
+ j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+ i0 &= 0xfffff;
+ i0 |= 0x100000;
+
+ 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
+ {
+ 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 int) i0;
+ else
+ result = ((long int) i0 << (j0 - 20)) | (i1 >> (52 - j0));
+ }
+ }
+ else
+ {
+ /* The number is too large. It is left implementation defined
+ what happens. */
+ return (long int) x;
+ }
+
+ return sx ? -result : result;
+}
+libm_hidden_def(lrint)