add fdlibm

git-svn-id: http://svn2.nishi.boats/svn/milsko/trunk@557 b9cfdab3-6d41-4d17-bbe4-086880011989

external/fdlibm/e_remainder.c

@@ -0,0 +1,65 @@
+
+/* @(#)e_remainder.c 1.3 95/01/18 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+/* __fdlibm_remainder(x,p)
+ * Return :
+ * 	returns  x REM p  =  x - [x/p]*p as if in infinite
+ * 	precise arithmetic, where [x/p] is the (infinite bit)
+ *	integer nearest x/p (in half way case choose the even one).
+ * Method :
+ *	Based on fmod() return x-[x/p]chopped*p exactlp.
+ */
+
+#include "math.h"
+
+static const double zero = 0.0;
+
+double __fdlibm_remainder(double x, double p) {
+	int	 hx, hp;
+	unsigned sx, lx, lp;
+	double	 p_half;
+
+	hx = __HI(x); /* high word of x */
+	lx = __LO(x); /* low  word of x */
+	hp = __HI(p); /* high word of p */
+	lp = __LO(p); /* low  word of p */
+	sx = hx & 0x80000000;
+	hp &= 0x7fffffff;
+	hx &= 0x7fffffff;
+
+	/* purge off exception values */
+	if((hp | lp) == 0) return (x * p) / (x * p); /* p = 0 */
+	if((hx >= 0x7ff00000) ||		     /* x not finite */
+	   ((hp >= 0x7ff00000) &&		     /* p is NaN */
+	    (((hp - 0x7ff00000) | lp) != 0)))
+		return (x * p) / (x * p);
+
+	if(hp <= 0x7fdfffff) x = __fdlibm_fmod(x, p + p); /* now x < 2p */
+	if(((hx - hp) | (lx - lp)) == 0) return zero * x;
+	x = fabs(x);
+	p = fabs(p);
+	if(hp < 0x00200000) {
+		if(x + x > p) {
+			x -= p;
+			if(x + x >= p) x -= p;
+		}
+	} else {
+		p_half = 0.5 * p;
+		if(x > p_half) {
+			x -= p;
+			if(x >= p_half) x -= p;
+		}
+	}
+	__HI(x) ^= sx;
+	return x;
+}