From be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da Mon Sep 17 00:00:00 2001
From: rgrimes <rgrimes@FreeBSD.org>
Date: Fri, 27 May 1994 05:00:24 +0000
Subject: BSD 4.4 Lite Lib Sources

---
 lib/libm/common_source/log10.c | 95 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 lib/libm/common_source/log10.c

(limited to 'lib/libm/common_source/log10.c')

diff --git a/lib/libm/common_source/log10.c b/lib/libm/common_source/log10.c
new file mode 100644
index 0000000..d2617cc
--- /dev/null
+++ b/lib/libm/common_source/log10.c
@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 1985, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)log10.c	8.1 (Berkeley) 6/4/93";
+#endif /* not lint */
+
+/* LOG10(X)
+ * RETURN THE BASE 10 LOGARITHM OF x
+ * DOUBLE PRECISION (VAX D format 56 bits, IEEE DOUBLE 53 BITS)
+ * CODED IN C BY K.C. NG, 1/20/85; 
+ * REVISED BY K.C. NG on 1/23/85, 3/7/85, 4/16/85.
+ * 
+ * Required kernel function:
+ *	log(x)
+ *
+ * Method :
+ *			     log(x)
+ *		log10(x) = ---------  or  [1/log(10)]*log(x)
+ *			    log(10)
+ *
+ *    Note:
+ *	  [log(10)]   rounded to 56 bits has error  .0895  ulps,
+ *	  [1/log(10)] rounded to 53 bits has error  .198   ulps;
+ *	  therefore, for better accuracy, in VAX D format, we divide 
+ *	  log(x) by log(10), but in IEEE Double format, we multiply 
+ *	  log(x) by [1/log(10)].
+ *
+ * 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.
+ *
+ * Accuracy:
+ *	log10(X) returns the exact log10(x) nearly rounded. In a test run
+ *	with 1,536,000 random arguments on a VAX, the maximum observed
+ *	error was 1.74 ulps (units in the last place).
+ *
+ * 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 "mathimpl.h"
+
+vc(ln10hi, 2.3025850929940456790E0 ,5d8d,4113,a8ac,ddaa, 2, .935D8DDDAAA8AC)
+
+ic(ivln10, 4.3429448190325181667E-1, -2, 1.BCB7B1526E50E)
+
+#ifdef vccast
+#define	ln10hi	vccast(ln10hi)
+#endif
+
+
+double log10(x)
+double x;
+{
+#if defined(vax)||defined(tahoe)
+	return(log(x)/ln10hi);
+#else	/* defined(vax)||defined(tahoe) */
+	return(ivln10*log(x));
+#endif	/* defined(vax)||defined(tahoe) */
+}
-- 
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