summaryrefslogtreecommitdiff
path: root/newlib/libm/math/w_log10.c
diff options
context:
space:
mode:
Diffstat (limited to 'newlib/libm/math/w_log10.c')
-rw-r--r--newlib/libm/math/w_log10.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/newlib/libm/math/w_log10.c b/newlib/libm/math/w_log10.c
new file mode 100644
index 00000000000..f427b86ccd7
--- /dev/null
+++ b/newlib/libm/math/w_log10.c
@@ -0,0 +1,115 @@
+
+/* @(#)w_log10.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * 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
+ <<log10>>, <<log10f>>---base 10 logarithms
+
+INDEX
+log10
+INDEX
+log10f
+
+ANSI_SYNOPSIS
+ #include <math.h>
+ double log10(double <[x]>);
+ float log10f(float <[x]>);
+
+TRAD_SYNOPSIS
+ #include <math.h>
+ double log10(<[x]>)
+ double <[x]>;
+
+ float log10f(<[x]>)
+ float <[x]>;
+
+DESCRIPTION
+<<log10>> returns the base 10 logarithm of <[x]>.
+It is implemented as <<log(<[x]>) / log(10)>>.
+
+<<log10f>> is identical, save that it takes and returns <<float>> values.
+
+RETURNS
+<<log10>> and <<log10f>> return the calculated value.
+
+See the description of <<log>> for information on errors.
+
+PORTABILITY
+<<log10>> is ANSI C. <<log10f>> is an extension.
+
+ */
+
+/*
+ * wrapper log10(X)
+ */
+
+#include "fdlibm.h"
+#include <errno.h>
+
+#ifndef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+ double log10(double x) /* wrapper log10 */
+#else
+ double log10(x) /* wrapper log10 */
+ double x;
+#endif
+{
+#ifdef _IEEE_LIBM
+ return __ieee754_log10(x);
+#else
+ double z;
+ struct exception exc;
+ z = __ieee754_log10(x);
+ if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
+ if(x<=0.0) {
+#ifndef HUGE_VAL
+#define HUGE_VAL inf
+ double inf = 0.0;
+
+ SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */
+#endif
+ exc.name = "log10";
+ exc.err = 0;
+ exc.arg1 = x;
+ exc.arg2 = x;
+ if (_LIB_VERSION == _SVID_)
+ exc.retval = -HUGE;
+ else
+ exc.retval = -HUGE_VAL;
+ if(x==0.0) {
+ /* log10(0) */
+ exc.type = SING;
+ if (_LIB_VERSION == _POSIX_)
+ errno = ERANGE;
+ else if (!matherr(&exc)) {
+ errno = EDOM;
+ }
+ } else {
+ /* log10(x<0) */
+ exc.type = DOMAIN;
+ if (_LIB_VERSION == _POSIX_)
+ errno = EDOM;
+ else if (!matherr(&exc)) {
+ errno = EDOM;
+ }
+ }
+ if (exc.err != 0)
+ errno = exc.err;
+ return exc.retval;
+ } else
+ return z;
+#endif
+}
+
+#endif /* defined(_DOUBLE_IS_32BITS) */