1 files changed, 89 insertions, 0 deletions
diff --git a/libm/src/e_sqrtf.c b/libm/src/e_sqrtf.c
new file mode 100644
index 0000000..edc9ef2
--- /dev/null
+++ b/libm/src/e_sqrtf.c
@@ -0,0 +1,89 @@
+/* e_sqrtf.c -- float version of e_sqrt.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.
+ * ====================================================
+ */
+
+#ifndef lint
+static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_sqrtf.c,v 1.7 2002/05/28 18:15:04 alfred Exp $";
+#endif
+
+#include "math.h"
+#include "math_private.h"
+
+static	const float	one	= 1.0, tiny=1.0e-30;
+
+float
+__ieee754_sqrtf(float x)
+{
+	float z;
+	int32_t sign = (int)0x80000000;
+	int32_t ix,s,q,m,t,i;
+	u_int32_t r;
+
+	GET_FLOAT_WORD(ix,x);
+
+    /* take care of Inf and NaN */
+	if((ix&0x7f800000)==0x7f800000) {
+	    return x*x+x;		/* sqrt(NaN)=NaN, sqrt(+inf)=+inf
+					   sqrt(-inf)=sNaN */
+	}
+    /* take care of zero */
+	if(ix<=0) {
+	    if((ix&(~sign))==0) return x;/* sqrt(+-0) = +-0 */
+	    else if(ix<0)
+		return (x-x)/(x-x);		/* sqrt(-ve) = sNaN */
+	}
+    /* normalize x */
+	m = (ix>>23);
+	if(m==0) {				/* subnormal x */
+	    for(i=0;(ix&0x00800000)==0;i++) ix<<=1;
+	    m -= i-1;
+	}
+	m -= 127;	/* unbias exponent */
+	ix = (ix&0x007fffff)|0x00800000;
+	if(m&1)	/* odd m, double x to make it even */
+	    ix += ix;
+	m >>= 1;	/* m = [m/2] */
+
+    /* generate sqrt(x) bit by bit */
+	ix += ix;
+	q = s = 0;		/* q = sqrt(x) */
+	r = 0x01000000;		/* r = moving bit from right to left */
+
+	while(r!=0) {
+	    t = s+r;
+	    if(t<=ix) {
+		s    = t+r;
+		ix  -= t;
+		q   += r;
+	    }
+	    ix += ix;
+	    r>>=1;
+	}
+
+    /* use floating add to find out rounding direction */
+	if(ix!=0) {
+	    z = one-tiny; /* trigger inexact flag */
+	    if (z>=one) {
+	        z = one+tiny;
+		if (z>one)
+		    q += 2;
+		else
+		    q += (q&1);
+	    }
+	}
+	ix = (q>>1)+0x3f000000;
+	ix += (m <<23);
+	SET_FLOAT_WORD(z,ix);
+	return z;
+}