--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libquadmath/math/atan2q.c	Sun Aug 21 07:07:55 2011 +0900
@@ -0,0 +1,120 @@
+/* e_atan2l.c -- long double version of e_atan2.c.
+ * Conversion to long double by Jakub Jelinek, jj@ultra.linux.cz.
+ */
+
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+/* atan2q(y,x)
+ * Method :
+ *	1. Reduce y to positive by atan2q(y,x)=-atan2q(-y,x).
+ *	2. Reduce x to positive by (if x and y are unexceptional):
+ *		ARG (x+iy) = arctan(y/x)   	   ... if x > 0,
+ *		ARG (x+iy) = pi - arctan[y/(-x)]   ... if x < 0,
+ *
+ * Special cases:
+ *
+ *	ATAN2((anything), NaN ) is NaN;
+ *	ATAN2(NAN , (anything) ) is NaN;
+ *	ATAN2(+-0, +(anything but NaN)) is +-0  ;
+ *	ATAN2(+-0, -(anything but NaN)) is +-pi ;
+ *	ATAN2(+-(anything but 0 and NaN), 0) is +-pi/2;
+ *	ATAN2(+-(anything but INF and NaN), +INF) is +-0 ;
+ *	ATAN2(+-(anything but INF and NaN), -INF) is +-pi;
+ *	ATAN2(+-INF,+INF ) is +-pi/4 ;
+ *	ATAN2(+-INF,-INF ) is +-3pi/4;
+ *	ATAN2(+-INF, (anything but,0,NaN, and INF)) is +-pi/2;
+ *
+ * Constants:
+ * The hexadecimal values are the intended ones for the following
+ * constants. The decimal values may be used, provided that the
+ * compiler will convert from decimal to binary accurately enough
+ * to produce the hexadecimal values shown.
+ */
+
+#include "quadmath-imp.h"
+
+static const __float128
+tiny  = 1.0e-4900Q,
+zero  = 0.0,
+pi_o_4  = 7.85398163397448309615660845819875699e-01Q, /* 3ffe921fb54442d18469898cc51701b8 */
+pi_o_2  = 1.57079632679489661923132169163975140e+00Q, /* 3fff921fb54442d18469898cc51701b8 */
+pi      = 3.14159265358979323846264338327950280e+00Q, /* 4000921fb54442d18469898cc51701b8 */
+pi_lo   = 8.67181013012378102479704402604335225e-35Q; /* 3f8dcd129024e088a67cc74020bbea64 */
+
+__float128
+atan2q (__float128 y, __float128 x)
+{
+	__float128 z;
+	int64_t k,m,hx,hy,ix,iy;
+	uint64_t lx,ly;
+
+	GET_FLT128_WORDS64(hx,lx,x);
+	ix = hx&0x7fffffffffffffffLL;
+	GET_FLT128_WORDS64(hy,ly,y);
+	iy = hy&0x7fffffffffffffffLL;
+	if(((ix|((lx|-lx)>>63))>0x7fff000000000000LL)||
+	   ((iy|((ly|-ly)>>63))>0x7fff000000000000LL))	/* x or y is NaN */
+	   return x+y;
+	if(((hx-0x3fff000000000000LL)|lx)==0) return atanq(y);   /* x=1.0Q */
+	m = ((hy>>63)&1)|((hx>>62)&2);	/* 2*sign(x)+sign(y) */
+
+    /* when y = 0 */
+	if((iy|ly)==0) {
+	    switch(m) {
+		case 0:
+		case 1: return y; 	/* atan(+-0,+anything)=+-0 */
+		case 2: return  pi+tiny;/* atan(+0,-anything) = pi */
+		case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */
+	    }
+	}
+    /* when x = 0 */
+	if((ix|lx)==0) return (hy<0)?  -pi_o_2-tiny: pi_o_2+tiny;
+
+    /* when x is INF */
+	if(ix==0x7fff000000000000LL) {
+	    if(iy==0x7fff000000000000LL) {
+		switch(m) {
+		    case 0: return  pi_o_4+tiny;/* atan(+INF,+INF) */
+		    case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */
+		    case 2: return  3.0Q*pi_o_4+tiny;/*atan(+INF,-INF)*/
+		    case 3: return -3.0Q*pi_o_4-tiny;/*atan(-INF,-INF)*/
+		}
+	    } else {
+		switch(m) {
+		    case 0: return  zero  ;	/* atan(+...,+INF) */
+		    case 1: return -zero  ;	/* atan(-...,+INF) */
+		    case 2: return  pi+tiny  ;	/* atan(+...,-INF) */
+		    case 3: return -pi-tiny  ;	/* atan(-...,-INF) */
+		}
+	    }
+	}
+    /* when y is INF */
+	if(iy==0x7fff000000000000LL) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;
+
+    /* compute y/x */
+	k = (iy-ix)>>48;
+	if(k > 120) z=pi_o_2+0.5Q*pi_lo; 	/* |y/x| >  2**120 */
+	else if(hx<0&&k<-120) z=0.0Q; 		/* |y|/x < -2**120 */
+	else z=atanq(fabsq(y/x));		/* safe to do y/x */
+	switch (m) {
+	    case 0: return       z  ;	/* atan(+,+) */
+	    case 1: {
+	    	      uint64_t zh;
+		      GET_FLT128_MSW64(zh,z);
+		      SET_FLT128_MSW64(z,zh ^ 0x8000000000000000ULL);
+		    }
+		    return       z  ;	/* atan(-,+) */
+	    case 2: return  pi-(z-pi_lo);/* atan(+,-) */
+	    default: /* case 3 */
+	    	    return  (z-pi_lo)-pi;/* atan(-,-) */
+	}
+}