1 files changed, 97 insertions, 0 deletions
diff --git a/libm/src/e_atan2f.c b/libm/src/e_atan2f.c
new file mode 100644
index 0000000..466d5d4
--- /dev/null
+++ b/libm/src/e_atan2f.c
@@ -0,0 +1,97 @@
+/* e_atan2f.c -- float version of e_atan2.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_atan2f.c,v 1.7 2004/06/02 17:09:05 bde Exp $";
+#endif
+
+#include "math.h"
+#include "math_private.h"
+
+static const float
+tiny  = 1.0e-30,
+zero  = 0.0,
+pi_o_4  = 7.8539818525e-01, /* 0x3f490fdb */
+pi_o_2  = 1.5707963705e+00, /* 0x3fc90fdb */
+pi      = 3.1415927410e+00, /* 0x40490fdb */
+pi_lo   = -8.7422776573e-08; /* 0xb3bbbd2e */
+
+float
+__ieee754_atan2f(float y, float x)
+{
+	float z;
+	int32_t k,m,hx,hy,ix,iy;
+
+	GET_FLOAT_WORD(hx,x);
+	ix = hx&0x7fffffff;
+	GET_FLOAT_WORD(hy,y);
+	iy = hy&0x7fffffff;
+	if((ix>0x7f800000)||
+	   (iy>0x7f800000))	/* x or y is NaN */
+	   return x+y;
+	if(hx==0x3f800000) return atanf(y);   /* x=1.0 */
+	m = ((hy>>31)&1)|((hx>>30)&2);	/* 2*sign(x)+sign(y) */
+
+    /* when y = 0 */
+	if(iy==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==0) return (hy<0)?  -pi_o_2-tiny: pi_o_2+tiny;
+
+    /* when x is INF */
+	if(ix==0x7f800000) {
+	    if(iy==0x7f800000) {
+		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  (float)3.0*pi_o_4+tiny;/*atan(+INF,-INF)*/
+		    case 3: return (float)-3.0*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==0x7f800000) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;
+
+    /* compute y/x */
+	k = (iy-ix)>>23;
+	if(k > 60) z=pi_o_2+(float)0.5*pi_lo; 	/* |y/x| >  2**60 */
+	else if(hx<0&&k<-60) z=0.0; 	/* |y|/x < -2**60 */
+	else z=atanf(fabsf(y/x));	/* safe to do y/x */
+	switch (m) {
+	    case 0: return       z  ;	/* atan(+,+) */
+	    case 1: {
+	    	      u_int32_t zh;
+		      GET_FLOAT_WORD(zh,z);
+		      SET_FLOAT_WORD(z,zh ^ 0x80000000);
+		    }
+		    return       z  ;	/* atan(-,+) */
+	    case 2: return  pi-(z-pi_lo);/* atan(+,-) */
+	    default: /* case 3 */
+	    	    return  (z-pi_lo)-pi;/* atan(-,-) */
+	}
+}