1 files changed, 88 insertions, 0 deletions
diff --git a/modules/fdlibm/src/e_logf.cpp b/modules/fdlibm/src/e_logf.cpp
new file mode 100644
index 0000000000..a878e9d32d
--- /dev/null
+++ b/modules/fdlibm/src/e_logf.cpp
@@ -0,0 +1,88 @@
+/* e_logf.c -- float version of e_log.c.
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * 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("$FreeBSD$");
+
+#include "math_private.h"
+
+static const float
+ln2_hi =   6.9313812256e-01,	/* 0x3f317180 */
+ln2_lo =   9.0580006145e-06,	/* 0x3717f7d1 */
+two25 =    3.355443200e+07,	/* 0x4c000000 */
+/* |(log(1+s)-log(1-s))/s - Lg(s)| < 2**-34.24 (~[-4.95e-11, 4.97e-11]). */
+Lg1 =      0xaaaaaa.0p-24,	/* 0.66666662693 */
+Lg2 =      0xccce13.0p-25,	/* 0.40000972152 */
+Lg3 =      0x91e9ee.0p-25,	/* 0.28498786688 */
+Lg4 =      0xf89e26.0p-26;	/* 0.24279078841 */
+
+static const float zero   =  0.0;
+static volatile float vzero = 0.0;
+
+float
+__ieee754_logf(float x)
+{
+	float hfsq,f,s,z,R,w,t1,t2,dk;
+	int32_t k,ix,i,j;
+
+	GET_FLOAT_WORD(ix,x);
+
+	k=0;
+	if (ix < 0x00800000) {			/* x < 2**-126  */
+	    if ((ix&0x7fffffff)==0)
+		return -two25/vzero;		/* log(+-0)=-inf */
+	    if (ix<0) return (x-x)/zero;	/* log(-#) = NaN */
+	    k -= 25; x *= two25; /* subnormal number, scale up x */
+	    GET_FLOAT_WORD(ix,x);
+	}
+	if (ix >= 0x7f800000) return x+x;
+	k += (ix>>23)-127;
+	ix &= 0x007fffff;
+	i = (ix+(0x95f64<<3))&0x800000;
+	SET_FLOAT_WORD(x,ix|(i^0x3f800000));	/* normalize x or x/2 */
+	k += (i>>23);
+	f = x-(float)1.0;
+	if((0x007fffff&(0x8000+ix))<0xc000) {	/* -2**-9 <= f < 2**-9 */
+	    if(f==zero) {
+		if(k==0) {
+		    return zero;
+		} else {
+		    dk=(float)k;
+		    return dk*ln2_hi+dk*ln2_lo;
+		}
+	    }
+	    R = f*f*((float)0.5-(float)0.33333333333333333*f);
+	    if(k==0) return f-R; else {dk=(float)k;
+	    	     return dk*ln2_hi-((R-dk*ln2_lo)-f);}
+	}
+ 	s = f/((float)2.0+f);
+	dk = (float)k;
+	z = s*s;
+	i = ix-(0x6147a<<3);
+	w = z*z;
+	j = (0x6b851<<3)-ix;
+	t1= w*(Lg2+w*Lg4);
+	t2= z*(Lg1+w*Lg3);
+	i |= j;
+	R = t2+t1;
+	if(i>0) {
+	    hfsq=(float)0.5*f*f;
+	    if(k==0) return f-(hfsq-s*(hfsq+R)); else
+		     return dk*ln2_hi-((hfsq-(s*(hfsq+R)+dk*ln2_lo))-f);
+	} else {
+	    if(k==0) return f-s*(f-R); else
+		     return dk*ln2_hi-((s*(f-R)-dk*ln2_lo)-f);
+	}
+}