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, 110 insertions, 0 deletions

diff --git a/usr/src/lib/libm/common/C/exp10.c b/usr/src/lib/libm/common/C/exp10.c
new file mode 100644
index 0000000000..f259ed0a9a
--- /dev/null
+++ b/usr/src/lib/libm/common/C/exp10.c
@@ -0,0 +1,110 @@
+/*
+ * 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 exp10 = __exp10
+
+/* INDENT OFF */
+/*
+ * exp10(x)
+ * Code by K.C. Ng for SUN 4.0 libm.
+ * Method :
+ *	n = nint(x*(log10/log2));
+ *	exp10(x) = 10**x = exp(x*ln(10)) = exp(n*ln2+(x*ln10-n*ln2))
+ *		 = 2**n*exp(ln10*(x-n*log2/log10)))
+ *	If x is an integer < 23 then use repeat multiplication. For
+ *	10**22 is the largest representable integer.
+ */
+/* INDENT ON */
+
+#include "libm.h"
+
+static const double C[] = {
+	3.3219280948736234787,	/* log(10)/log(2) */
+	2.3025850929940456840,	/* log(10) */
+	3.0102999565860955045E-1,	/* log(2)/log(10) high */
+	5.3716447674669983622E-12,	/* log(2)/log(10) low */
+	0.0,
+	0.5,
+	1.0,
+	10.0,
+	1.0e300,
+	1.0e-300,
+};
+
+#define	lg10	C[0]
+#define	ln10	C[1]
+#define	logt2hi	C[2]
+#define	logt2lo	C[3]
+#define	zero	C[4]
+#define	half	C[5]
+#define	one	C[6]
+#define	ten	C[7]
+#define	huge	C[8]
+#define	tiny	C[9]
+
+double
+exp10(double x) {
+	double	t, pt;
+	int	ix, hx, k;
+
+	ix = ((int *)&x)[HIWORD];
+	hx = ix & ~0x80000000;
+
+	if (hx >= 0x4074a000) {	/* |x| >= 330 or x is nan */
+		if (hx >= 0x7ff00000) {	/* x is inf or nan */
+			if (ix == 0xfff00000 && ((int *)&x)[LOWORD] == 0)
+				return (zero);
+			return (x * x);
+		}
+		t = (ix < 0)? tiny : huge;
+		return (t * t);
+	}
+
+	if (hx < 0x3c000000)
+		return (one + x);
+
+	k = (int)x;
+	if (0 <= k && k < 23 && (double)k == x) {
+		/* x is a small positive integer */
+		t = one;
+		pt = ten;
+		if (k & 1)
+			t = ten;
+		k >>= 1;
+		while (k) {
+			pt *= pt;
+			if (k & 1)
+				t *= pt;
+			k >>= 1;
+		}
+		return (t);
+	}
+	t = x * lg10;
+	k = (int)((ix < 0)? t - half : t + half);
+	return (scalbn(exp(ln10 * ((x - k * logt2hi) - k * logt2lo)), k));
+}