--- /dev/null	Sat May 10 12:09:18 2014
+++ new/usr/src/lib/libm/common/complex/catan.c	Sat May 10 12:09:18 2014
@@ -0,0 +1,292 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ */
+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma weak catan = __catan
+
+/* INDENT OFF */
+/*
+ * dcomplex catan(dcomplex z);
+ *
+ * If
+ *     z = x + iy,
+ *
+ * then
+ *          1       (    2x     )    1                2    2
+ * Re w  =  - arctan(-----------)  = - ATAN2(2x, 1 - x  - y )
+ *          2       (     2    2)    2
+ *                  (1 - x  - y )
+ *
+ *               ( 2         2)
+ *          1    (x  +  (y+1) )      1                  4y
+ * Im w  =  - log(------------) .=  --- log [ 1 + ------------- ]
+ *          4    ( 2         2)      4              2         2
+ *               (x  +  (y-1) )                    x  +  (y-1)
+ *
+ *                 2    16  3                         y
+ *         = t - 2t   + -- t  - ..., where t = -----------------
+ *                      3                      x*x + (y-1)*(y-1)
+ *
+ * Note that: if catan( x, y) = ( u, v), then
+ *               catan(-x, y) = (-u, v)
+ *               catan( x,-y) = ( u,-v)
+ *
+ * Also,   catan(x,y) = -i*catanh(-y,x), or
+ *        catanh(x,y) =  i*catan(-y,x)
+ * So, if catanh(y,x) = (v,u), then catan(x,y) = -i*(-v,u) = (u,v), i.e.,
+ *	  catan(x,y) = (u,v)
+ *
+ * EXCEPTION CASES (conform to ISO/IEC 9899:1999(E)):
+ *    catan( 0  , 0   ) =  (0    ,  0   )
+ *    catan( NaN, 0   ) =  (NaN  ,  0   )
+ *    catan( 0  , 1   ) =  (0    ,  +inf) with divide-by-zero
+ *    catan( inf, y   ) =  (pi/2 ,  0   ) for finite +y
+ *    catan( NaN, y   ) =  (NaN  ,  NaN ) with invalid for finite y!=0
+ *    catan( x  , inf ) =  (pi/2 ,  0   ) for finite +x
+ *    catan( inf, inf ) =  (pi/2 ,  0   )
+ *    catan( NaN, inf ) =  (NaN  ,  0   )
+ *    catan( x  , NaN ) =  (NaN  ,  NaN ) with invalid for finite x
+ *    catan( inf, NaN ) =  (pi/2 ,  +-0 )
+ */
+/* INDENT ON */
+
+#include "libm.h"		/* atan/atan2/fabs/log/log1p */
+#include "complex_wrapper.h"
+
+/* INDENT OFF */
+static const double
+	pi_2 = 1.570796326794896558e+00,
+	zero = 0.0,
+	half = 0.5,
+	two = 2.0,
+	ln2 = 6.931471805599453094172321214581765680755e-0001,
+	one = 1.0;
+/* INDENT ON */
+
+dcomplex
+catan(dcomplex z) {
+	dcomplex ans;
+	double x, y, ax, ay, t;
+	int hx, hy, ix, iy;
+	unsigned lx, ly;
+
+	x = D_RE(z);
+	y = D_IM(z);
+	ax = fabs(x);
+	ay = fabs(y);
+	hx = HI_WORD(x);
+	lx = LO_WORD(x);
+	hy = HI_WORD(y);
+	ly = LO_WORD(y);
+	ix = hx & 0x7fffffff;
+	iy = hy & 0x7fffffff;
+
+	/* x is inf or NaN */
+	if (ix >= 0x7ff00000) {
+		if (ISINF(ix, lx)) {
+			D_RE(ans) = pi_2;
+			D_IM(ans) = zero;
+		} else {
+			D_RE(ans) = x + x;
+			if ((iy | ly) == 0 || (ISINF(iy, ly)))
+				D_IM(ans) = zero;
+			else
+				D_IM(ans) = (fabs(y) - ay) / (fabs(y) - ay);
+		}
+	} else if (iy >= 0x7ff00000) {
+		/* y is inf or NaN */
+		if (ISINF(iy, ly)) {
+			D_RE(ans) = pi_2;
+			D_IM(ans) = zero;
+		} else {
+			D_RE(ans) = (fabs(x) - ax) / (fabs(x) - ax);
+			D_IM(ans) = y;
+		}
+	} else if ((ix | lx) == 0) {
+		/* INDENT OFF */
+		/*
+		 * x = 0
+		 *      1                            1
+		 * A = --- * atan2(2x, 1-x*x-y*y) = --- atan2(0,1-|y|)
+		 *      2                            2
+		 *
+		 *     1     [  (y+1)*(y+1) ]   1          2      1         2y
+		 * B = - log [ ------------ ] = - log (1+ ---) or - log(1+ ----)
+		 *     4     [  (y-1)*(y-1) ]   2         y-1     2         1-y
+		 */
+		/* INDENT ON */
+		t = one - ay;
+		if (((iy - 0x3ff00000) | ly) == 0) {
+			/* y=1: catan(0,1)=(0,+inf) with 1/0 signal */
+			D_IM(ans) = ay / ax;
+			D_RE(ans) = zero;
+		} else if (iy >= 0x3ff00000) {	/* y>1 */
+			D_IM(ans) = half * log1p(two / (-t));
+			D_RE(ans) = pi_2;
+		} else {		/* y<1 */
+			D_IM(ans) = half * log1p((ay + ay) / t);
+			D_RE(ans) = zero;
+		}
+	} else if (iy < 0x3e200000 || ((ix - iy) >> 20) >= 30) {
+	/* INDENT OFF */
+	/*
+	 * Tiny y (relative to 1+|x|)
+	 *     |y| < E*(1+|x|)
+	 * where E=2**-29, -35, -60 for double, double extended, quad precision
+	 *
+	 *      1                           [ x<=1:   atan(x)
+	 * A = --- * atan2(2x, 1-x*x-y*y) ~ [       1                 1+x
+	 *      2                           [ x>=1: - atan2(2,(1-x)*(-----))
+	 *                                          2                  x
+	 *
+	 *                               y/x
+	 * B ~ t*(1-2t), where t = ----------------- is tiny
+	 *                         x + (y-1)*(y-1)/x
+	 */
+		/* INDENT ON */
+		if (ix < 0x3ff00000)
+			D_RE(ans) = atan(ax);
+		else
+			D_RE(ans) = half * atan2(two, (one - ax) * (one +
+				one / ax));
+		if ((iy | ly) == 0) {
+			D_IM(ans) = ay;
+		} else {
+			if (ix < 0x3e200000)
+				t = ay / ((ay - one) * (ay - one));
+			else if (ix > 0x41c00000)
+				t = (ay / ax) / ax;
+			else
+				t = ay / (ax * ax + (ay - one) * (ay - one));
+			D_IM(ans) = t * (one - (t + t));
+		}
+	} else if (iy >= 0x41c00000 && ((iy - ix) >> 20) >= 30) {
+		/* INDENT OFF */
+		/*
+		 * Huge y relative to 1+|x|
+		 *            |y| > Einv*(1+|x|), where Einv~2**(prec/2+3),
+		 *            1
+		 *       A ~ --- * atan2(2x, -y*y) ~ pi/2
+		 *            2
+		 *                                     y
+		 *       B ~ t*(1-2t), where t = --------------- is tiny
+		 *                                (y-1)*(y-1)
+		 */
+		/* INDENT ON */
+		D_RE(ans) = pi_2;
+		t = (ay / (ay - one)) / (ay - one);
+		D_IM(ans) = t * (one - (t + t));
+	} else if (((iy - 0x3ff00000) | ly) == 0) {
+		/* INDENT OFF */
+		/*
+		 * y = 1
+		 *      1                       1
+		 * A = --- * atan2(2x, -x*x) = --- atan2(2,-x)
+		 *      2                       2
+		 *
+		 *     1     [x*x + 4]   1          4     [ 0.5(log2-logx) if
+		 * B = - log [-------] = - log (1+ ---) = [ |x|<E, else 0.25*
+		 *     4     [  x*x  ]   4         x*x    [ log1p((2/x)*(2/x))
+		 */
+		/* INDENT ON */
+		D_RE(ans) = half * atan2(two, -ax);
+		if (ix < 0x3e200000)
+			D_IM(ans) = half * (ln2 - log(ax));
+		else {
+			t = two / ax;
+			D_IM(ans) = 0.25 * log1p(t * t);
+		}
+	} else if (ix >= 0x43900000) {
+		/* INDENT OFF */
+		/*
+		 * Huge x:
+		 * when |x| > 1/E^2,
+		 *      1                           pi
+		 * A ~ --- * atan2(2x, -x*x-y*y) ~ ---
+		 *      2                           2
+		 *                               y                 y/x
+		 * B ~ t*(1-2t), where t = --------------- = (-------------- )/x
+		 *                         x*x+(y-1)*(y-1)     1+((y-1)/x)^2
+		 */
+		/* INDENT ON */
+		D_RE(ans) = pi_2;
+		t = ((ay / ax) / (one + ((ay - one) / ax) * ((ay - one) /
+			ax))) / ax;
+		D_IM(ans) = t * (one - (t + t));
+	} else if (ix < 0x38b00000) {
+		/* INDENT OFF */
+		/*
+		 * Tiny x:
+		 * when |x| < E^4,  (note that y!=1)
+		 *      1                            1
+		 * A = --- * atan2(2x, 1-x*x-y*y) ~ --- * atan2(2x,(1-y)*(1+y))
+		 *      2                            2
+		 *
+		 *     1     [(y+1)*(y+1)]   1          2      1         2y
+		 * B = - log [-----------] = - log (1+ ---) or - log(1+ ----)
+		 *     4     [(y-1)*(y-1)]   2         y-1     2         1-y
+		 */
+		/* INDENT ON */
+		D_RE(ans) = half * atan2(ax + ax, (one - ay) * (one + ay));
+		if (iy >= 0x3ff00000)
+			D_IM(ans) = half * log1p(two / (ay - one));
+		else
+			D_IM(ans) = half * log1p((ay + ay) / (one - ay));
+	} else {
+		/* INDENT OFF */
+		/*
+		 * normal x,y
+		 *      1
+		 * A = --- * atan2(2x, 1-x*x-y*y)
+		 *      2
+		 *
+		 *     1     [x*x+(y+1)*(y+1)]   1               4y
+		 * B = - log [---------------] = - log (1+ -----------------)
+		 *     4     [x*x+(y-1)*(y-1)]   4         x*x + (y-1)*(y-1)
+		 */
+		/* INDENT ON */
+		t = one - ay;
+		if (iy >= 0x3fe00000 && iy < 0x40000000) {
+			/* y close to 1 */
+			D_RE(ans) = half * (atan2((ax + ax), (t * (one + ay) -
+				ax * ax)));
+		} else if (ix >= 0x3fe00000 && ix < 0x40000000) {
+			/* x close to 1 */
+			D_RE(ans) = half * atan2((ax + ax), ((one - ax) *
+				(one + ax) - ay * ay));
+		} else
+			D_RE(ans) = half * atan2((ax + ax), ((one - ax * ax) -
+				ay * ay));
+		D_IM(ans) = 0.25 * log1p((4.0 * ay) / (ax * ax + t * t));
+	}
+	if (hx < 0)
+		D_RE(ans) = -D_RE(ans);
+	if (hy < 0)
+		D_IM(ans) = -D_IM(ans);
+	return (ans);
+}
