[src/trunk]: src/lib/libm/src FreeBSD version

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ac3be91e93fa
branches:  trunk
changeset: 784796:ac3be91e93fa
user:      christos <christos%NetBSD.org@localhost>
date:      Sat Feb 09 22:32:47 2013 +0000

description:
FreeBSD version

diffstat:

 lib/libm/src/s_rintl.c |  90 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 90 insertions(+), 0 deletions(-)

diffs (94 lines):

diff -r fbac5e0a9ddd -r ac3be91e93fa lib/libm/src/s_rintl.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/libm/src/s_rintl.c    Sat Feb 09 22:32:47 2013 +0000
@@ -0,0 +1,90 @@
+/*-
+ * Copyright (c) 2008 David Schultz <das%FreeBSD.ORG@localhost>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: src/lib/msun/src/s_rintl.c,v 1.5 2008/02/22 11:59:05 bde Exp $");
+
+#include <float.h>
+#include <math.h>
+
+#include "fpmath.h"
+
+#if LDBL_MAX_EXP != 0x4000
+/* We also require the usual bias, min exp and expsign packing. */
+#error "Unsupported long double format"
+#endif
+
+#define        BIAS    (LDBL_MAX_EXP - 1)
+
+static const float
+shift[2] = {
+#if LDBL_MANT_DIG == 64
+       0x1.0p63, -0x1.0p63
+#elif LDBL_MANT_DIG == 113
+       0x1.0p112, -0x1.0p112
+#else
+#error "Unsupported long double format"
+#endif
+};
+static const float zero[2] = { 0.0, -0.0 };
+
+long double
+rintl(long double x)
+{
+       union IEEEl2bits u;
+       uint32_t expsign;
+       int ex, sign;
+
+       u.e = x;
+       expsign = u.xbits.expsign;
+       ex = expsign & 0x7fff;
+
+       if (ex >= BIAS + LDBL_MANT_DIG - 1) {
+               if (ex == BIAS + LDBL_MAX_EXP)
+                       return (x + x); /* Inf, NaN, or unsupported format */
+               return (x);             /* finite and already an integer */
+       }
+       sign = expsign >> 15;
+
+       /*
+        * The following code assumes that intermediate results are
+        * evaluated in long double precision. If they are evaluated in
+        * greater precision, double rounding may occur, and if they are
+        * evaluated in less precision (as on i386), results will be
+        * wildly incorrect.
+        */
+       x += shift[sign];
+       x -= shift[sign];
+
+       /*
+        * If the result is +-0, then it must have the same sign as x, but
+        * the above calculation doesn't always give this.  Fix up the sign.
+        */
+       if (ex < BIAS && x == 0.0L)
+               return (zero[sign]);
+
+       return (x);
+}