693 Opensource replacement of sunwlibm

Reviewed by: Igor Kozhukhov ikozhukhov@gmail.com
Reviewed by: Keith M Wesolowski <keith.wesolowski@joyent.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Dan McDonald <danmcd@omniti.com>

1 files changed, 134 insertions, 0 deletions

diff --git a/usr/src/lib/libm/common/complex/clog.c b/usr/src/lib/libm/common/complex/clog.c
new file mode 100644
index 0000000000..eb8492e4bf
--- /dev/null
+++ b/usr/src/lib/libm/common/complex/clog.c
@@ -0,0 +1,134 @@
+/*
+ * 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 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma weak clog = __clog
+
+/* INDENT OFF */
+/*
+ * dcomplex clog(dcomplex z);
+ *
+ *                    _________
+ *                   / 2    2            -1   y
+ * log(x+iy) = log(\/ x  + y    ) + i tan   (---)
+ *                                            x
+ *
+ *              1       2    2         -1   y
+ *           = --- log(x  + y ) + i tan   (---)
+ *              2                           x
+ *
+ * Note that the arctangent ranges from -PI to +PI, thus the imaginary
+ * part of clog is atan2(y,x).
+ *
+ * EXCEPTION CASES (conform to ISO/IEC 9899:1999(E)):
+ *    clog(-0 + i 0   ) =  -inf + i pi
+ *    clog( 0 + i 0   ) =  -inf + i 0
+ *    clog( x + i inf ) =  -inf + i pi/2, for finite x
+ *    clog( x + i NaN ) =  NaN  + i NaN with invalid for finite x
+ *    clog(-inf + iy   )=  +inf + i pi, for finite positive-signed y
+ *    clog(+inf + iy   )=  +inf + i 0 , for finite positive-signed y
+ *    clog(-inf + i inf)=  inf  + i 3pi/4
+ *    clog(+inf + i inf)=  inf  + i pi/4
+ *    clog(+-inf+ i NaN)=  inf  + i NaN
+ *    clog(NaN  + i y  )=  NaN  + i NaN for finite y
+ *    clog(NaN  + i inf)=  inf  + i NaN
+ *    clog(NaN  + i NaN)=  NaN  + i NaN
+ */
+/* INDENT ON */
+
+#include "libm_synonyms.h"
+#include <math.h>		/* atan2/fabs/log/log1p */
+#include "complex_wrapper.h"
+#include "libm_protos.h"	/* __k_clog_r */
+
+
+static const double half = 0.5, one = 1.0;
+
+dcomplex
+clog(dcomplex z) {
+	dcomplex	ans;
+	double		x, y, t, ax, ay, w;
+	int		n, ix, iy, hx, hy;
+	unsigned	lx, ly;
+
+	x = D_RE(z);
+	y = D_IM(z);
+	hx = HI_WORD(x);
+	lx = LO_WORD(x);
+	hy = HI_WORD(y);
+	ly = LO_WORD(y);
+	ix = hx & 0x7fffffff;
+	iy = hy & 0x7fffffff;
+	ay = fabs(y);
+	ax = fabs(x);
+	D_IM(ans) = carg(z);
+	if (ix < iy || (ix == iy && lx < ly)) {
+		/* swap x and y to force ax >= ay */
+		t = ax;
+		ax = ay;
+		ay = t;
+		n = ix, ix = iy;
+		iy = n;
+		n = lx, lx = ly;
+		ly = n;
+	}
+	n = (ix - iy) >> 20;
+	if (ix >= 0x7ff00000) {	/* x or y is Inf or NaN */
+		if (ISINF(ix, lx))
+			D_RE(ans) = ax;
+		else if (ISINF(iy, ly))
+			D_RE(ans) = ay;
+		else
+			D_RE(ans) = ax * ay;
+	} else if ((iy | ly) == 0) {
+		D_RE(ans) = ((ix | lx) == 0)? -one / ax : log(ax);
+	} else if (((0x3fffffff - ix) ^ (ix - 0x3fe00000)) >= 0) {
+		/* 0.5 <= x < 2 */
+		if (ix >= 0x3ff00000) {
+			if (((ix - 0x3ff00000) | lx) == 0)
+				D_RE(ans) = half * log1p(ay * ay);
+			else if (n >= 60)
+				D_RE(ans) = log(ax);
+			else
+				D_RE(ans) = half * (log1p(ay * ay + (ax -
+				    one) * (ax + one)));
+		} else if (n >= 60) {
+			D_RE(ans) = log(ax);
+		} else {
+			D_RE(ans) = __k_clog_r(ax, ay, &w);
+		}
+	} else if (n >= 30) {
+		D_RE(ans) = log(ax);
+	} else if (ix < 0x5f300000 && iy >= 0x20b00000) {
+		/* 2**-500< y < x < 2**500 */
+		D_RE(ans) = half * log(ax * ax + ay * ay);
+	} else {
+		t = ay / ax;
+		D_RE(ans) = log(ax) + half * log1p(t * t);
+	}
+	return (ans);
+}