1 files changed, 61 insertions, 0 deletions
diff --git a/usr/src/lib/libm/common/Q/atanhl.c b/usr/src/lib/libm/common/Q/atanhl.c
new file mode 100644
index 0000000000..f7462ca1ef
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+++ b/usr/src/lib/libm/common/Q/atanhl.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 2011 Nexenta Systems, Inc.  All rights reserved.
+ */
+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma weak atanhl = __atanhl
+
+#include "libm.h"
+
+/*
+ *                   1              2x                           x
+ *	atanhl(x) = --- * LOG(1 + -------) = 0.5 * log1pl(2 * --------)
+ *                   2             1 - x                       1 - x
+ * Note: to guarantee atanhl(-x) = -atanhl(x), we use
+ *                  sign(x)              |x|
+ *	atanhl(x) = ------- * log1pl(2*-------).
+ *                     2               1 - |x|
+ *
+ * Special cases:
+ *	atanhl(x) is NaN if |x| > 1 with signal;
+ *	atanhl(NaN) is that NaN with no signal;
+ *	atanhl(+-1) is +-INF with signal.
+ *
+ */
+
+static const long double zero = 0.0L, half = 0.5L, one = 1.0L;
+
+long double
+atanhl(long double x) {
+	long double t;
+
+	t = fabsl(x);
+	if (t == one)
+		return (x / zero);
+	t = t / (one - t);
+	return (copysignl(half, x) * log1pl(t + t));
+}