693 Opensource replacement of sunwlibm

Reviewed by: Igor Kozhukhov ikozhukhov@gmail.com
Reviewed by: Keith M Wesolowski <keith.wesolowski@joyent.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Dan McDonald <danmcd@omniti.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/usr/src/lib/libm/common/C/remainder.c b/usr/src/lib/libm/common/C/remainder.c
new file mode 100644
index 0000000000..ababc45cfb
--- /dev/null
+++ b/usr/src/lib/libm/common/C/remainder.c
@@ -0,0 +1,87 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ */
+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma weak remainder = __remainder
+
+/*
+ * remainder(x,p)
+ * Code originated from 4.3bsd.
+ * Modified by K.C. Ng for SUN 4.0 libm.
+ * Return :
+ * 	returns  x REM p  =  x - [x/p]*p as if in infinite precise arithmetic,
+ *	where [x/p] is the (inifinite bit) integer nearest x/p (in half way
+ *	case choose the even one).
+ * Method :
+ *	Based on fmod() return x-[x/p]chopped*p exactly.
+ */
+
+#include "libm.h"
+
+static const double zero = 0.0, half = 0.5;
+
+double
+remainder(double x, double p) {
+	double	halfp;
+	int	ix, hx, hp;
+
+	ix = ((int *)&x)[HIWORD];
+	hx = ix & ~0x80000000;
+	hp = ((int *)&p)[HIWORD] & ~0x80000000;
+
+	if (hp > 0x7ff00000 || (hp == 0x7ff00000 && ((int *)&p)[LOWORD] != 0))
+		return (x * p);
+	if (hx > 0x7ff00000 || (hx == 0x7ff00000 && ((int *)&x)[LOWORD] != 0))
+		return (x * p);
+
+	if ((hp | ((int *)&p)[LOWORD]) == 0 || hx == 0x7ff00000)
+		return (_SVID_libm_err(x, p, 28));
+
+	p = fabs(p);
+	if (hp < 0x7fe00000)
+		x = fmod(x, p + p);
+	x = fabs(x);
+	if (hp < 0x00200000) {
+		if (x + x > p) {
+			if (x == p)	/* avoid x-x=-0 in RM mode */
+				return ((ix < 0)? -zero : zero);
+			x -= p;
+			if (x + x >= p)
+				x -= p;
+		}
+	} else {
+		halfp = half * p;
+		if (x > halfp) {
+			if (x == p)	/* avoid x-x=-0 in RM mode */
+				return ((ix < 0)? -zero : zero);
+			x -= p;
+			if (x >= halfp)
+				x -= p;
+		}
+	}
+	return ((ix < 0)? -x : x);
+}