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, 160 insertions, 0 deletions

diff --git a/usr/src/lib/libm/common/Q/atan2l.c b/usr/src/lib/libm/common/Q/atan2l.c
new file mode 100644
index 0000000000..d7a538cd2b
--- /dev/null
+++ b/usr/src/lib/libm/common/Q/atan2l.c
@@ -0,0 +1,160 @@
+/*
+ * 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.
+ */
+
+/*
+ * atan2l(y,x)
+ *
+ * Method :
+ *	1. Reduce y to positive by atan2(y,x)=-atan2(-y,x).
+ *	2. Reduce x to positive by (if x and y are unexceptional):
+ *		ARG (x+iy) = arctan(y/x)	   ... if x > 0,
+ *		ARG (x+iy) = pi - arctan[y/(-x)]   ... if x < 0,
+ *
+ * Special cases:
+ *
+ *	ATAN2((anything), NaN ) is NaN;
+ *	ATAN2(NAN , (anything) ) is NaN;
+ *	ATAN2(+-0, +(anything but NaN)) is +-0  ;
+ *	ATAN2(+-0, -(anything but NaN)) is +-PI ;
+ *	ATAN2(+-(anything but 0 and NaN), 0) is +-PI/2;
+ *	ATAN2(+-(anything but INF and NaN), +INF) is +-0 ;
+ *	ATAN2(+-(anything but INF and NaN), -INF) is +-PI;
+ *	ATAN2(+-INF,+INF ) is +-PI/4 ;
+ *	ATAN2(+-INF,-INF ) is +-3PI/4;
+ *	ATAN2(+-INF, (anything but,0,NaN, and INF)) is +-PI/2;
+ *
+ * Constants:
+ * The hexadecimal values are the intended ones for the following constants.
+ * The decimal values may be used, provided that the compiler will convert
+ * from decimal to binary accurately enough to produce the hexadecimal values
+ * shown.
+ */
+
+#pragma weak atan2l = __atan2l
+
+#include "libm.h"
+#include "longdouble.h"
+
+static const long double
+	zero	=  0.0L,
+	tiny 	=  1.0e-40L,
+	one	=  1.0L,
+	half	=  0.5L,
+	PI3o4	=  2.356194490192344928846982537459627163148L,
+	PIo4	=  0.785398163397448309615660845819875721049L,
+	PIo2	=  1.570796326794896619231321691639751442099L,
+	PI	=  3.141592653589793238462643383279502884197L,
+	PI_lo	=  8.671810130123781024797044026043351968762e-35L;
+
+long double
+atan2l(long double y, long double x) {
+	long double t, z;
+	int k, m, signy, signx;
+
+	if (x != x || y != y)
+		return (x + y);	/* return NaN if x or y is NAN */
+	signy = signbitl(y);
+	signx = signbitl(x);
+	if (x == one)
+		return (atanl(y));
+	m = signy + signx + signx;
+
+	/* when y = 0 */
+	if (y == zero)
+		switch (m) {
+		case 0:
+			return (y);	/* atan(+0,+anything) */
+		case 1:
+			return (y);	/* atan(-0,+anything) */
+		case 2:
+			return (PI + tiny);	/* atan(+0,-anything) */
+		case 3:
+			return (-PI - tiny);	/* atan(-0,-anything) */
+		}
+
+	/* when x = 0 */
+	if (x == zero)
+		return (signy == 1 ? -PIo2 - tiny : PIo2 + tiny);
+
+	/* when x is INF */
+	if (!finitel(x)) {
+		if (!finitel(y)) {
+			switch (m) {
+			case 0:
+				return (PIo4 + tiny);	/* atan(+INF,+INF) */
+			case 1:
+				return (-PIo4 - tiny);	/* atan(-INF,+INF) */
+			case 2:
+				return (PI3o4 + tiny);	/* atan(+INF,-INF) */
+			case 3:
+				return (-PI3o4 - tiny);	/* atan(-INF,-INF) */
+			}
+		} else {
+			switch (m) {
+			case 0:
+				return (zero);	/* atan(+...,+INF) */
+			case 1:
+				return (-zero);	/* atan(-...,+INF) */
+			case 2:
+				return (PI + tiny);	/* atan(+...,-INF) */
+			case 3:
+				return (-PI - tiny);	/* atan(-...,-INF) */
+			}
+		}
+	}
+	/* when y is INF */
+	if (!finitel(y))
+		return (signy == 1 ? -PIo2 - tiny : PIo2 + tiny);
+
+	/* compute y/x */
+	x = fabsl(x);
+	y = fabsl(y);
+	t = PI_lo;
+	k = (ilogbl(y) - ilogbl(x));
+
+	if (k > 120)
+		z = PIo2 + half * t;
+	else if (m > 1 && k < -120)
+		z = zero;
+	else
+		z = atanl(y / x);
+
+	switch (m) {
+	case 0:
+		return (z);	/* atan(+,+) */
+	case 1:
+		return (-z);	/* atan(-,+) */
+	case 2:
+		return (PI - (z - t));	/* atan(+,-) */
+	case 3:
+		return ((z - t) - PI);	/* atan(-,-) */
+	}
+	/* NOTREACHED */
+    return 0.0L;
+}