2009-03-18 Yaakov Selkowitz <yselkowitz@users.sourceforge.net>

        * libm/common/s_log2.c: New file.
        * libm/common/sf_log2.c: Ditto.
        * libm/common/Makefile.am: Add s_log2.c and sf_log2.c.
        * libm/common/Makefile.in: Regenerated.
        * libc/include/math.h: Add log2 and log2f function prototypes.

1 files changed, 73 insertions, 0 deletions

diff --git a/newlib/libm/common/s_log2.c b/newlib/libm/common/s_log2.c
new file mode 100644
index 000000000..4683960eb
--- /dev/null
+++ b/newlib/libm/common/s_log2.c
@@ -0,0 +1,73 @@
+/* @(#)s_log2.c 5.1 93/09/24 */
+/* Modification from s_exp10.c Yaakov Selkowitz 2009.  */
+
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+/*
+FUNCTION
+	<<log2>>, <<log2f>>---base 2 logarithm
+INDEX
+	log2
+INDEX
+	log2f
+
+ANSI_SYNOPSIS
+	#include <math.h>
+	double log2(double <[x]>);
+	float log2f(float <[x]>);
+
+TRAD_SYNOPSIS
+	#include <math.h>
+	double log2(<[x]>);
+	double <[x]>;
+
+	float log2f(<[x]>);
+	float <[x]>;
+
+DESCRIPTION
+	<<log2>> returns the base 2 logarithm of <[x]>.
+
+	<<log2f>> is identical, save that it takes and returns <<float>> values.
+
+RETURNS
+	On success, <<log2>> and <<log2f>> return the calculated value.
+	If the result underflows, the returned value is <<0>>.  If the
+	result overflows, the returned value is <<HUGE_VAL>>.  In
+	either case, <<errno>> is set to <<ERANGE>>.
+
+PORTABILITY
+	<<log2>> and <<log2f>> are required by ISO/IEC 9899:1999 and the
+	System V Interface Definition (Issue 6).
+*/
+
+/*
+ * wrapper log2(x)
+ */
+
+#include "fdlibm.h"
+#include <errno.h>
+#include <math.h>
+#undef log2
+
+#ifndef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+	double log2(double x)		/* wrapper log2 */
+#else
+	double log2(x)			/* wrapper log2 */
+	double x;
+#endif
+{
+  return (log(x) / M_LOG2_E);
+}
+
+#endif /* defined(_DOUBLE_IS_32BITS) */