1 files changed, 68 insertions, 0 deletions
diff --git a/usr/src/libm/src/Q/cbrtl.c b/usr/src/libm/src/Q/cbrtl.c
new file mode 100644
index 0000000..a9c697a
--- /dev/null
+++ b/usr/src/libm/src/Q/cbrtl.c
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+/*
+ * 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 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident	"@(#)cbrtl.c	1.7	06/01/31 SMI"
+
+#pragma weak cbrtl = __cbrtl
+
+#include "libm.h"
+
+#define	n0	0
+
+long double
+cbrtl(long double x) {
+	long double s, t, r, w, y;
+	double dx, dy;
+	int *py = (int *) &dy;
+	int n, m, m3, sx;
+
+	if (!finitel(x))
+		return (x + x);
+	if (iszerol(x))
+		return (x);
+	sx = signbitl(x);
+	x = fabsl(x);
+	n = ilogbl(x);
+	m = n / 3;
+	m3 = m + m + m;
+	y = scalbnl(x, -m3);
+	dx = (double) y;
+	dy = cbrt(dx);
+	py[1 - n0] += 2;
+	if (py[1 - n0] == 0)
+		py[n0] += 1;
+
+	/* one step newton iteration to 113 bits with error < 0.667ulps */
+	t = (long double) dy;
+	t = scalbnl(t, m);
+	s = t * t;
+	r = x / s;
+	w = t + t;
+	r = (r - t) / (w + r);
+	t += t * r;
+
+	return (sx == 0 ? t : -t);
+}