1 files changed, 114 insertions, 0 deletions
diff --git a/src/math/atan2l.c b/src/math/atan2l.c
new file mode 100644
index 00000000..64ec12e7
--- /dev/null
+++ b/src/math/atan2l.c
@@ -0,0 +1,114 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_atan2l.c */
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ *
+ */
+/*
+ * See comments in atan2.c.
+ * Converted to long double by David Schultz <das@FreeBSD.ORG>.
+ */
+
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double atan2l(long double y, long double x)
+{
+	return atan2(y, x);
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+#include "__invtrigl.h"
+static volatile long double
+tiny = 1.0e-300;
+static const long double
+zero = 0.0;
+/* XXX Work around the fact that gcc truncates long double constants on i386 */
+static volatile double
+pi1 = 3.14159265358979311600e+00, /* 0x1.921fb54442d18p+1  */
+pi2 = 1.22514845490862001043e-16; /* 0x1.1a80000000000p-53 */
+#define pi ((long double)pi1 + pi2)
+#if 0
+static const long double
+pi = 3.14159265358979323846264338327950280e+00L;
+#endif
+
+long double atan2l(long double y, long double x)
+{
+	union IEEEl2bits ux, uy;
+	long double z;
+	int32_t k,m;
+	int16_t exptx, expsignx, expty, expsigny;
+
+	uy.e = y;
+	expsigny = uy.xbits.expsign;
+	expty = expsigny & 0x7fff;
+	ux.e = x;
+	expsignx = ux.xbits.expsign;
+	exptx = expsignx & 0x7fff;
+	if ((exptx==BIAS+LDBL_MAX_EXP &&
+	     ((ux.bits.manh&~LDBL_NBIT)|ux.bits.manl)!=0) || /* x is NaN */
+	    (expty==BIAS+LDBL_MAX_EXP &&
+	     ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl)!=0))   /* y is NaN */
+		return x+y;
+	if (expsignx==BIAS && ((ux.bits.manh&~LDBL_NBIT)|ux.bits.manl)==0) /* x=1.0 */
+		return atanl(y);
+	m = ((expsigny>>15)&1) | ((expsignx>>14)&2);  /* 2*sign(x)+sign(y) */
+
+	/* when y = 0 */
+	if (expty==0 && ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl)==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 (exptx==0 && ((ux.bits.manh&~LDBL_NBIT)|ux.bits.manl)==0)
+		return expsigny < 0 ? -pio2_hi-tiny : pio2_hi+tiny;
+	/* when x is INF */
+	if (exptx == BIAS+LDBL_MAX_EXP) {
+		if (expty == BIAS+LDBL_MAX_EXP) {
+			switch(m) {
+			case 0: return  pio2_hi*0.5+tiny; /* atan(+INF,+INF) */
+			case 1: return -pio2_hi*0.5-tiny; /* atan(-INF,+INF) */
+			case 2: return  1.5*pio2_hi+tiny; /*atan(+INF,-INF)*/
+			case 3: return -1.5*pio2_hi-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 (expty == BIAS+LDBL_MAX_EXP)
+		return expsigny < 0 ? -pio2_hi-tiny : pio2_hi+tiny;
+
+	/* compute y/x */
+	k = expty-exptx;
+	if(k > LDBL_MANT_DIG+2) { /* |y/x| huge */
+		z = pio2_hi+pio2_lo;
+		m &= 1;
+	} else if (expsignx < 0 && k < -LDBL_MANT_DIG-2) /* |y/x| tiny, x<0 */
+		z = 0.0;
+	else                     /* safe to do y/x */
+		z = atanl(fabsl(y/x));
+	switch (m) {
+	case 0: return z;              /* atan(+,+) */
+	case 1: return -z;             /* atan(-,+) */
+	case 2: return pi - (z-pi_lo); /* atan(+,-) */
+	default: /* case 3 */
+		return (z-pi_lo) - pi; /* atan(-,-) */
+	}
+}
+#endif