xref: /illumos-gate/usr/src/lib/libm/common/complex/clogl.c (revision 9b9d39d2a32ff806d2431dbcc50968ef1e6d46b2)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
24  */
25 /*
26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
27  * Use is subject to license terms.
28  */
29 
30 #pragma weak __clogl = clogl
31 
32 #include "libm.h"	/* atan2l/fabsl/isinfl/log1pl/logl/__k_clog_rl */
33 #include "complex_wrapper.h"
34 #include "longdouble.h"
35 
36 #if defined(__sparc)
37 #define	SIGP7	120
38 #define	HSIGP7	60
39 #elif defined(__x86)
40 #define	SIGP7	70
41 #define	HSIGP7	35
42 #endif
43 
44 /* INDENT OFF */
45 static const long double zero = 0.0L, half = 0.5L, one = 1.0L;
46 /* INDENT ON */
47 
48 ldcomplex
49 clogl(ldcomplex z) {
50 	ldcomplex ans;
51 	long double x, y, t, ax, ay;
52 	int n, ix, iy, hx, hy;
53 
54 	x = LD_RE(z);
55 	y = LD_IM(z);
56 	hx = HI_XWORD(x);
57 	hy = HI_XWORD(y);
58 	ix = hx & 0x7fffffff;
59 	iy = hy & 0x7fffffff;
60 	ay = fabsl(y);
61 	ax = fabsl(x);
62 	LD_IM(ans) = atan2l(y, x);
63 	if (ix < iy || (ix == iy && ix < 0x7fff0000 && ax < ay)) {
64 			/* swap x and y to force ax>=ay */
65 		t = ax;
66 		ax = ay;
67 		ay = t;
68 		n = ix, ix = iy;
69 		iy = n;
70 	}
71 	n = (ix - iy) >> 16;
72 	if (ix >= 0x7fff0000) {	/* x or y is Inf or NaN */
73 		if (isinfl(ax))
74 			LD_RE(ans) = ax;
75 		else if (isinfl(ay))
76 			LD_RE(ans) = ay;
77 		else
78 			LD_RE(ans) = ax + ay;
79 	} else if (ay == zero)
80 		LD_RE(ans) = logl(ax);
81 	else if (((0x3fffffff - ix) ^ (ix - 0x3ffe0000)) >= 0) {
82 							/* 0.5 <= x < 2 */
83 		if (ix >= 0x3fff0000) {
84 			if (ax == one)
85 				LD_RE(ans) = half * log1pl(ay * ay);
86 			else if (n >= SIGP7)
87 				LD_RE(ans) = logl(ax);
88 			else
89 				LD_RE(ans) = half * (log1pl(ay * ay + (ax -
90 					one) * (ax + one)));
91 		} else if (n >= SIGP7)
92 			LD_RE(ans) = logl(ax);
93 		else
94 			LD_RE(ans) = __k_clog_rl(x, y, &t);
95 	} else if (n >= HSIGP7)
96 		LD_RE(ans) = logl(ax);
97 	else if (ix < 0x5f3f0000 && iy >= 0x20bf0000)
98 		/* 2**-8000 < y < x < 2**8000 */
99 		LD_RE(ans) = half * logl(ax * ax + ay * ay);
100 	else {
101 		t = ay / ax;
102 		LD_RE(ans) = logl(ax) + half * log1pl(t * t);
103 	}
104 	return (ans);
105 }
106