1 files changed, 72 insertions, 0 deletions
diff --git a/modules/fdlibm/src/e_log10f.cpp b/modules/fdlibm/src/e_log10f.cpp
new file mode 100644
index 0000000000..cf3ccd5445
--- /dev/null
+++ b/modules/fdlibm/src/e_log10f.cpp
@@ -0,0 +1,72 @@
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+//#include <sys/cdefs.h>
+//__FBSDID("$FreeBSD$");
+
+/*
+ * Float version of e_log10.c.  See the latter for most comments.
+ */
+
+#include "math.h"
+#include "math_private.h"
+#include "k_logf.h"
+
+static const float
+two25      =  3.3554432000e+07, /* 0x4c000000 */
+ivln10hi   =  4.3432617188e-01, /* 0x3ede6000 */
+ivln10lo   = -3.1689971365e-05, /* 0xb804ead9 */
+log10_2hi  =  3.0102920532e-01, /* 0x3e9a2080 */
+log10_2lo  =  7.9034151668e-07; /* 0x355427db */
+
+static const float zero   =  0.0;
+static volatile float vzero = 0.0;
+
+float
+__ieee754_log10f(float x)
+{
+	float f,hfsq,hi,lo,r,y;
+	int32_t i,k,hx;
+
+	GET_FLOAT_WORD(hx,x);
+
+	k=0;
+	if (hx < 0x00800000) {			/* x < 2**-126  */
+	    if ((hx&0x7fffffff)==0)
+		return -two25/vzero;		/* log(+-0)=-inf */
+	    if (hx<0) return (x-x)/zero;	/* log(-#) = NaN */
+	    k -= 25; x *= two25; /* subnormal number, scale up x */
+	    GET_FLOAT_WORD(hx,x);
+	}
+	if (hx >= 0x7f800000) return x+x;
+	if (hx == 0x3f800000)
+	    return zero;			/* log(1) = +0 */
+	k += (hx>>23)-127;
+	hx &= 0x007fffff;
+	i = (hx+(0x4afb0d))&0x800000;
+	SET_FLOAT_WORD(x,hx|(i^0x3f800000));	/* normalize x or x/2 */
+	k += (i>>23);
+	y = (float)k;
+	f = x - (float)1.0;
+	hfsq = (float)0.5*f*f;
+	r = k_log1pf(f);
+
+	/* See e_log2f.c and e_log2.c for details. */
+	if (sizeof(float_t) > sizeof(float))
+		return (r - hfsq + f) * ((float_t)ivln10lo + ivln10hi) +
+		    y * ((float_t)log10_2lo + log10_2hi);
+	hi = f - hfsq;
+	GET_FLOAT_WORD(hx,hi);
+	SET_FLOAT_WORD(hi,hx&0xfffff000);
+	lo = (f - hi) - hfsq + r;
+	return y*log10_2lo + (lo+hi)*ivln10lo + lo*ivln10hi + hi*ivln10hi +
+	    y*log10_2hi;
+}