1 files changed, 58 insertions, 0 deletions
diff --git a/lib/msun/src/e_log2f.c b/lib/msun/src/e_log2f.c
new file mode 100644
index 0000000..bb308d3
--- /dev/null
+++ b/lib/msun/src/e_log2f.c
@@ -0,0 +1,58 @@
+/*
+ * ====================================================
+ * 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("$FreeBSD$");
+
+/*
+ * Return the base 2 logarithm of x. See k_log.c for details on the algorithm.
+ */
+
+#include "math.h"
+#include "math_private.h"
+#include "k_logf.h"
+
+static const float
+two25      =  3.3554432000e+07, /* 0x4c000000 */
+ivln2hi    =  1.4428710938e+00, /* 0x3fb8b000 */
+ivln2lo    = -1.7605285393e-04; /* 0xb9389ad4 */
+
+static const float zero   =  0.0;
+
+float
+__ieee754_log2f(float x)
+{
+	float f,hi,lo;
+	int32_t i,k,hx;
+
+	GET_FLOAT_WORD(hx,x);
+
+        k=0;
+        if (hx < 0x00800000) {                  /* x < 2**-126  */
+            if ((hx&0x7fffffff)==0)
+                return -two25/zero;             /* 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;
+	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);
+	f = __kernel_logf(x);
+	x = x - (float)1.0;
+	GET_FLOAT_WORD(hx,x);
+	SET_FLOAT_WORD(hi,hx&0xfffff000);
+	lo = x - hi;
+	return (x+f)*ivln2lo + (lo+f)*ivln2hi + hi*ivln2hi + k;
+}