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/Q/log10l.c b/usr/src/lib/libm/common/Q/log10l.c
new file mode 100644
index 0000000000..9c83580531
--- /dev/null
+++ b/usr/src/lib/libm/common/Q/log10l.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.
+ */
+
+#if defined(ELFOBJ)
+#pragma weak log10l = __log10l
+#endif
+
+/*
+ * log10l(X)
+ *
+ * Method :
+ *	Let log10_2hi = leading 98(SPARC)/49(x86) bits of log10(2) and
+ *	    log10_2lo = log10(2) - log10_2hi,
+ *	    ivln10   = 1/log(10) rounded.
+ *	Then
+ *		n = ilogb(x),
+ *		if (n<0)  n = n+1;
+ *		x = scalbn(x,-n);
+ *		LOG10(x) := n*log10_2hi + (n*log10_2lo + ivln10*log(x))
+ *
+ * Note1:
+ *	For fear of destroying log10(10**n)=n, the rounding mode is
+ *	set to Round-to-Nearest.
+ *
+ * Special cases:
+ *	log10(x) is NaN with signal if x < 0;
+ *	log10(+INF) is +INF with no signal; log10(0) is -INF with signal;
+ *	log10(NaN) is that NaN with no signal;
+ *	log10(10**N) = N  for N=0,1,...,22.
+ *
+ * Constants:
+ * The hexadecimal values are the intended ones for the following constants.
+ * The decimal values may be used, provided that the compiler will convert
+ * from decimal to binary accurately enough to produce the hexadecimal values
+ * shown.
+ */
+
+#include "libm.h"
+#include "longdouble.h"
+
+#if defined(__x86)
+#define	__swapRD	__swap87RD
+#endif
+extern enum fp_direction_type __swapRD(enum fp_direction_type);
+
+static const long double
+	zero	  = 0.0L,
+	ivln10    = 4.342944819032518276511289189166050822944e-0001L,
+	one	  = 1.0L,
+#if defined(__x86)
+	log10_2hi = 3.010299956639803653501985536422580480576e-01L,
+	log10_2lo = 8.298635403410822349787106337291183585413e-16L;
+#elif defined(__sparc)
+	log10_2hi = 3.010299956639811952137388947242098603469e-01L,
+	log10_2lo = 2.831664213089468167896664371953210945664e-31L;
+#else
+#error Unknown Architecture!
+#endif
+
+long double
+log10l(long double x) {
+	long double y, z;
+	enum fp_direction_type rd;
+	int n;
+
+	if (!finitel(x))
+		return (x + fabsl(x));	/* x is +-INF or NaN */
+	else if (x > zero) {
+		n = ilogbl(x);
+		if (n < 0)
+			n += 1;
+		rd = __swapRD(fp_nearest);
+		y = n;
+		x = scalbnl(x, -n);
+		z = y * log10_2lo + ivln10 * logl(x);
+		z += y * log10_2hi;
+		if (rd != fp_nearest)
+			(void) __swapRD(rd);
+		return (z);
+	} else if (x == zero)	/* -INF */
+		return (-one / zero);
+	else			/* x <0, return NaN */
+		return (zero / zero);
+}