1 files changed, 67 insertions, 0 deletions
diff --git a/usr/src/lib/libm/common/Q/acosl.c b/usr/src/lib/libm/common/Q/acosl.c
new file mode 100644
index 0000000000..b4d77ff4e3
--- /dev/null
+++ b/usr/src/lib/libm/common/Q/acosl.c
@@ -0,0 +1,67 @@
+/*
+ * 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.
+ */
+
+/*
+ * arccosin function
+ *			      ________
+ *                           / 1 - x
+ *	acos(x) = 2*atan2(  / -------- , 1 )
+ *                        \/   1 + x
+ *
+ *			      ________
+ *                           / 1 - x
+ *		= 2*atan (  / -------- ) for non-exceptional x.
+ *                        \/   1 + x
+ *
+ * Special cases:
+ *	if x is NaN, return x itself;
+ *	if |x|>1, return NaN with invalid signal.
+ */
+
+#pragma weak acosl = __acosl
+
+#include "libm.h"
+
+static const long double zero = 0.0L, one = 1.0L;
+
+long double
+acosl(long double x) {
+	if (isnanl(x))
+		return (x + x);
+	else if (fabsl(x) < one)
+		x = atanl(sqrtl((one - x) / (one + x)));
+	else if (x == -one)
+		x = atan2l(one, zero);	/* x <- PI */
+	else if (x == one)
+		x = zero;
+	else {		/* |x| > 1  create invalid signal */
+		return (zero / zero);
+	}
+	return (x + x);
+}