1 files changed, 76 insertions, 0 deletions
diff --git a/usr/src/lib/libm/common/C/tan.c b/usr/src/lib/libm/common/C/tan.c
new file mode 100644
index 0000000000..7462e8f6b2
--- /dev/null
+++ b/usr/src/lib/libm/common/C/tan.c
@@ -0,0 +1,76 @@
+/*
+ * 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 tan = __tan
+
+/* INDENT OFF */
+/*
+ * tan(x)
+ * Table look-up algorithm by K.C. Ng, November, 1989.
+ *
+ * kernel function:
+ *	__k_tan		... tangent function on [-pi/4,pi/4]
+ *	__rem_pio2	... argument reduction routine
+ */
+/* INDENT ON */
+
+#include "libm.h"
+#include "libm_synonyms.h"
+#include "libm_protos.h"
+#include <math.h>
+
+double
+tan(double x) {
+	double y[2], z = 0.0;
+	int n, ix;
+
+	/* high word of x */
+	ix = ((int *) &x)[HIWORD];
+
+	/* |x| ~< pi/4 */
+	ix &= 0x7fffffff;
+	if (ix <= 0x3fe921fb)
+		return (__k_tan(x, z, 0));
+
+	/* tan(Inf or NaN) is NaN */
+	else if (ix >= 0x7ff00000) {
+#if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
+		return (ix >= 0x7ff80000 ? x : x - x);	/* NaN */
+		/* assumes sparc-like QNaN */
+#else
+		return (x - x);				/* NaN */
+#endif
+	}
+
+	/* argument reduction needed */
+	else {
+		n = __rem_pio2(x, y);
+		return (__k_tan(y[0], y[1], n & 1));
+	}
+}