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11175 libm should use signbit() correctly
11188 c99 math macros should return strictly backward compatible values
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--- old/usr/src/lib/libm/common/Q/atan2l.c
+++ new/usr/src/lib/libm/common/Q/atan2l.c
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License (the "License").
6 6 * You may not use this file except in compliance with the License.
7 7 *
8 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 9 * or http://www.opensolaris.org/os/licensing.
10 10 * See the License for the specific language governing permissions
11 11 * and limitations under the License.
12 12 *
13 13 * When distributing Covered Code, include this CDDL HEADER in each
14 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 15 * If applicable, add the following below this CDDL HEADER, with the
16 16 * fields enclosed by brackets "[]" replaced with your own identifying
17 17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 18 *
19 19 * CDDL HEADER END
20 20 */
21 21
22 22 /*
23 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 24 */
25 25 /*
26 26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 27 * Use is subject to license terms.
28 28 */
29 29
30 30 /*
31 31 * atan2l(y,x)
32 32 *
33 33 * Method :
34 34 * 1. Reduce y to positive by atan2(y,x)=-atan2(-y,x).
35 35 * 2. Reduce x to positive by (if x and y are unexceptional):
36 36 * ARG (x+iy) = arctan(y/x) ... if x > 0,
37 37 * ARG (x+iy) = pi - arctan[y/(-x)] ... if x < 0,
38 38 *
39 39 * Special cases:
40 40 *
41 41 * ATAN2((anything), NaN ) is NaN;
42 42 * ATAN2(NAN , (anything) ) is NaN;
43 43 * ATAN2(+-0, +(anything but NaN)) is +-0 ;
44 44 * ATAN2(+-0, -(anything but NaN)) is +-PI ;
45 45 * ATAN2(+-(anything but 0 and NaN), 0) is +-PI/2;
46 46 * ATAN2(+-(anything but INF and NaN), +INF) is +-0 ;
47 47 * ATAN2(+-(anything but INF and NaN), -INF) is +-PI;
48 48 * ATAN2(+-INF,+INF ) is +-PI/4 ;
49 49 * ATAN2(+-INF,-INF ) is +-3PI/4;
50 50 * ATAN2(+-INF, (anything but,0,NaN, and INF)) is +-PI/2;
51 51 *
52 52 * Constants:
53 53 * The hexadecimal values are the intended ones for the following constants.
54 54 * The decimal values may be used, provided that the compiler will convert
55 55 * from decimal to binary accurately enough to produce the hexadecimal values
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56 56 * shown.
57 57 */
58 58
59 59 #pragma weak __atan2l = atan2l
60 60
61 61 #include "libm.h"
62 62 #include "longdouble.h"
63 63
64 64 static const long double
65 65 zero = 0.0L,
66 - tiny = 1.0e-40L,
66 + tiny = 1.0e-40L,
67 67 one = 1.0L,
68 68 half = 0.5L,
69 69 PI3o4 = 2.356194490192344928846982537459627163148L,
70 70 PIo4 = 0.785398163397448309615660845819875721049L,
71 71 PIo2 = 1.570796326794896619231321691639751442099L,
72 72 PI = 3.141592653589793238462643383279502884197L,
73 73 PI_lo = 8.671810130123781024797044026043351968762e-35L;
74 74
75 75 long double
76 -atan2l(long double y, long double x) {
76 +atan2l(long double y, long double x)
77 +{
77 78 long double t, z;
78 79 int k, m, signy, signx;
79 80
80 81 if (x != x || y != y)
81 82 return (x + y); /* return NaN if x or y is NAN */
82 83 signy = signbitl(y);
83 84 signx = signbitl(x);
84 85 if (x == one)
85 86 return (atanl(y));
86 - m = signy + signx + signx;
87 + /* Ensure sign indicators are boolean */
88 + m = (signy != 0) + (signx != 0) + (signx != 0);
87 89
88 90 /* when y = 0 */
89 91 if (y == zero)
90 92 switch (m) {
91 93 case 0:
92 94 return (y); /* atan(+0,+anything) */
93 95 case 1:
94 96 return (y); /* atan(-0,+anything) */
95 97 case 2:
96 98 return (PI + tiny); /* atan(+0,-anything) */
97 99 case 3:
98 100 return (-PI - tiny); /* atan(-0,-anything) */
99 101 }
100 102
101 103 /* when x = 0 */
102 104 if (x == zero)
103 - return (signy == 1 ? -PIo2 - tiny : PIo2 + tiny);
105 + return (signy != 0 ? -PIo2 - tiny : PIo2 + tiny);
104 106
105 107 /* when x is INF */
106 108 if (!finitel(x)) {
107 109 if (!finitel(y)) {
108 110 switch (m) {
109 111 case 0:
110 112 return (PIo4 + tiny); /* atan(+INF,+INF) */
111 113 case 1:
112 114 return (-PIo4 - tiny); /* atan(-INF,+INF) */
113 115 case 2:
114 116 return (PI3o4 + tiny); /* atan(+INF,-INF) */
115 117 case 3:
116 118 return (-PI3o4 - tiny); /* atan(-INF,-INF) */
117 119 }
118 120 } else {
119 121 switch (m) {
120 122 case 0:
121 123 return (zero); /* atan(+...,+INF) */
122 124 case 1:
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123 125 return (-zero); /* atan(-...,+INF) */
124 126 case 2:
125 127 return (PI + tiny); /* atan(+...,-INF) */
126 128 case 3:
127 129 return (-PI - tiny); /* atan(-...,-INF) */
128 130 }
129 131 }
130 132 }
131 133 /* when y is INF */
132 134 if (!finitel(y))
133 - return (signy == 1 ? -PIo2 - tiny : PIo2 + tiny);
135 + return (signy != 0 ? -PIo2 - tiny : PIo2 + tiny);
134 136
135 137 /* compute y/x */
136 138 x = fabsl(x);
137 139 y = fabsl(y);
138 140 t = PI_lo;
139 141 k = (ilogbl(y) - ilogbl(x));
140 142
141 143 if (k > 120)
142 144 z = PIo2 + half * t;
143 145 else if (m > 1 && k < -120)
144 146 z = zero;
145 147 else
146 148 z = atanl(y / x);
147 149
148 150 switch (m) {
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149 151 case 0:
150 152 return (z); /* atan(+,+) */
151 153 case 1:
152 154 return (-z); /* atan(-,+) */
153 155 case 2:
154 156 return (PI - (z - t)); /* atan(+,-) */
155 157 case 3:
156 158 return ((z - t) - PI); /* atan(-,-) */
157 159 }
158 160 /* NOTREACHED */
159 - return 0.0L;
161 + return (0.0L);
160 162 }
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