1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate * CDDL HEADER START
3*0Sstevel@tonic-gate *
4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance
7*0Sstevel@tonic-gate * with the License.
8*0Sstevel@tonic-gate *
9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate * and limitations under the License.
13*0Sstevel@tonic-gate *
14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate *
20*0Sstevel@tonic-gate * CDDL HEADER END
21*0Sstevel@tonic-gate */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
24*0Sstevel@tonic-gate * Use is subject to license terms.
25*0Sstevel@tonic-gate */
26*0Sstevel@tonic-gate
27*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI"
28*0Sstevel@tonic-gate
29*0Sstevel@tonic-gate /*
30*0Sstevel@tonic-gate * _D_cplx_mul(z, w) returns z * w with infinities handled according
31*0Sstevel@tonic-gate * to C99.
32*0Sstevel@tonic-gate *
33*0Sstevel@tonic-gate * If z and w are both finite, _D_cplx_mul(z, w) delivers the complex
34*0Sstevel@tonic-gate * product according to the usual formula: let a = Re(z), b = Im(z),
35*0Sstevel@tonic-gate * c = Re(w), and d = Im(w); then _D_cplx_mul(z, w) delivers x + I * y
36*0Sstevel@tonic-gate * where x = a * c - b * d and y = a * d + b * c. Note that if both
37*0Sstevel@tonic-gate * ac and bd overflow, then at least one of ad or bc must also over-
38*0Sstevel@tonic-gate * flow, and vice versa, so that if one component of the product is
39*0Sstevel@tonic-gate * NaN, the other is infinite. (Such a value is considered infinite
40*0Sstevel@tonic-gate * according to C99.)
41*0Sstevel@tonic-gate *
42*0Sstevel@tonic-gate * If one of z or w is infinite and the other is either finite nonzero
43*0Sstevel@tonic-gate * or infinite, _D_cplx_mul delivers an infinite result. If one factor
44*0Sstevel@tonic-gate * is infinite and the other is zero, _D_cplx_mul delivers NaN + I * NaN.
45*0Sstevel@tonic-gate * C99 doesn't specify the latter case.
46*0Sstevel@tonic-gate *
47*0Sstevel@tonic-gate * C99 also doesn't specify what should happen if either z or w is a
48*0Sstevel@tonic-gate * complex NaN (i.e., neither finite nor infinite). This implementation
49*0Sstevel@tonic-gate * delivers NaN + I * NaN in this case.
50*0Sstevel@tonic-gate *
51*0Sstevel@tonic-gate * This implementation can raise spurious underflow, overflow, invalid
52*0Sstevel@tonic-gate * operation, and inexact exceptions. C99 allows this.
53*0Sstevel@tonic-gate */
54*0Sstevel@tonic-gate
55*0Sstevel@tonic-gate #if !defined(sparc) && !defined(__sparc)
56*0Sstevel@tonic-gate #error This code is for SPARC only
57*0Sstevel@tonic-gate #endif
58*0Sstevel@tonic-gate
59*0Sstevel@tonic-gate static union {
60*0Sstevel@tonic-gate int i[2];
61*0Sstevel@tonic-gate double d;
62*0Sstevel@tonic-gate } inf = {
63*0Sstevel@tonic-gate 0x7ff00000, 0
64*0Sstevel@tonic-gate };
65*0Sstevel@tonic-gate
66*0Sstevel@tonic-gate /*
67*0Sstevel@tonic-gate * Return +1 if x is +Inf, -1 if x is -Inf, and 0 otherwise
68*0Sstevel@tonic-gate */
69*0Sstevel@tonic-gate static int
testinf(double x)70*0Sstevel@tonic-gate testinf(double x)
71*0Sstevel@tonic-gate {
72*0Sstevel@tonic-gate union {
73*0Sstevel@tonic-gate int i[2];
74*0Sstevel@tonic-gate double d;
75*0Sstevel@tonic-gate } xx;
76*0Sstevel@tonic-gate
77*0Sstevel@tonic-gate xx.d = x;
78*0Sstevel@tonic-gate return (((((xx.i[0] << 1) - 0xffe00000) | xx.i[1]) == 0)?
79*0Sstevel@tonic-gate (1 | (xx.i[0] >> 31)) : 0);
80*0Sstevel@tonic-gate }
81*0Sstevel@tonic-gate
82*0Sstevel@tonic-gate double _Complex
_D_cplx_mul(double _Complex z,double _Complex w)83*0Sstevel@tonic-gate _D_cplx_mul(double _Complex z, double _Complex w)
84*0Sstevel@tonic-gate {
85*0Sstevel@tonic-gate double _Complex v;
86*0Sstevel@tonic-gate double a, b, c, d, x, y;
87*0Sstevel@tonic-gate int recalc, i, j;
88*0Sstevel@tonic-gate
89*0Sstevel@tonic-gate /*
90*0Sstevel@tonic-gate * The following is equivalent to
91*0Sstevel@tonic-gate *
92*0Sstevel@tonic-gate * a = creal(z); b = cimag(z);
93*0Sstevel@tonic-gate * c = creal(w); d = cimag(w);
94*0Sstevel@tonic-gate */
95*0Sstevel@tonic-gate a = ((double *)&z)[0];
96*0Sstevel@tonic-gate b = ((double *)&z)[1];
97*0Sstevel@tonic-gate c = ((double *)&w)[0];
98*0Sstevel@tonic-gate d = ((double *)&w)[1];
99*0Sstevel@tonic-gate
100*0Sstevel@tonic-gate x = a * c - b * d;
101*0Sstevel@tonic-gate y = a * d + b * c;
102*0Sstevel@tonic-gate
103*0Sstevel@tonic-gate if (x != x && y != y) {
104*0Sstevel@tonic-gate /*
105*0Sstevel@tonic-gate * Both x and y are NaN, so z and w can't both be finite.
106*0Sstevel@tonic-gate * If at least one of z or w is a complex NaN, and neither
107*0Sstevel@tonic-gate * is infinite, then we might as well deliver NaN + I * NaN.
108*0Sstevel@tonic-gate * So the only cases to check are when one of z or w is
109*0Sstevel@tonic-gate * infinite.
110*0Sstevel@tonic-gate */
111*0Sstevel@tonic-gate recalc = 0;
112*0Sstevel@tonic-gate i = testinf(a);
113*0Sstevel@tonic-gate j = testinf(b);
114*0Sstevel@tonic-gate if (i | j) { /* z is infinite */
115*0Sstevel@tonic-gate /* "factor out" infinity */
116*0Sstevel@tonic-gate a = i;
117*0Sstevel@tonic-gate b = j;
118*0Sstevel@tonic-gate recalc = 1;
119*0Sstevel@tonic-gate }
120*0Sstevel@tonic-gate i = testinf(c);
121*0Sstevel@tonic-gate j = testinf(d);
122*0Sstevel@tonic-gate if (i | j) { /* w is infinite */
123*0Sstevel@tonic-gate /* "factor out" infinity */
124*0Sstevel@tonic-gate c = i;
125*0Sstevel@tonic-gate d = j;
126*0Sstevel@tonic-gate recalc = 1;
127*0Sstevel@tonic-gate }
128*0Sstevel@tonic-gate if (recalc) {
129*0Sstevel@tonic-gate x = inf.d * (a * c - b * d);
130*0Sstevel@tonic-gate y = inf.d * (a * d + b * c);
131*0Sstevel@tonic-gate }
132*0Sstevel@tonic-gate }
133*0Sstevel@tonic-gate
134*0Sstevel@tonic-gate /*
135*0Sstevel@tonic-gate * The following is equivalent to
136*0Sstevel@tonic-gate *
137*0Sstevel@tonic-gate * return x + I * y;
138*0Sstevel@tonic-gate */
139*0Sstevel@tonic-gate ((double *)&v)[0] = x;
140*0Sstevel@tonic-gate ((double *)&v)[1] = y;
141*0Sstevel@tonic-gate return (v);
142*0Sstevel@tonic-gate }
143