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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2003 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* 28 * On SPARC V8, _Q_cplx_mul(v, z, w) sets *v = *z * *w with infinities 29 * handled according to C99. 30 * 31 * On SPARC V9, _Q_cplx_mul(z, w) returns *z * *w with infinities 32 * handled according to C99. 33 * 34 * If z and w are both finite, _Q_cplx_mul delivers the complex 35 * product according to the usual formula: let a = Re(z), b = Im(z), 36 * c = Re(w), and d = Im(w); then _Q_cplx_mul delivers x + I * y 37 * where x = a * c - b * d and y = a * d + b * c. Note that if both 38 * ac and bd overflow, then at least one of ad or bc must also over- 39 * flow, and vice versa, so that if one component of the product is 40 * NaN, the other is infinite. (Such a value is considered infinite 41 * according to C99.) 42 * 43 * If one of z or w is infinite and the other is either finite nonzero 44 * or infinite, _Q_cplx_mul delivers an infinite result. If one factor 45 * is infinite and the other is zero, _Q_cplx_mul delivers NaN + I * NaN. 46 * C99 doesn't specify the latter case. 47 * 48 * C99 also doesn't specify what should happen if either z or w is a 49 * complex NaN (i.e., neither finite nor infinite). This implementation 50 * delivers NaN + I * NaN in this case. 51 * 52 * This implementation can raise spurious underflow, overflow, invalid 53 * operation, and inexact exceptions. C99 allows this. 54 */ 55 56 #if !defined(sparc) && !defined(__sparc) 57 #error This code is for SPARC only 58 #endif 59 60 static union { 61 int i[4]; 62 long double q; 63 } inf = { 64 0x7fff0000, 0, 0, 0 65 }; 66 67 /* 68 * Return +1 if x is +Inf, -1 if x is -Inf, and 0 otherwise 69 */ 70 static int 71 testinfl(long double x) 72 { 73 union { 74 int i[4]; 75 long double q; 76 } xx; 77 78 xx.q = x; 79 return (((((xx.i[0] << 1) - 0xfffe0000) | xx.i[1] | xx.i[2] | xx.i[3]) 80 == 0)? (1 | (xx.i[0] >> 31)) : 0); 81 } 82 83 #ifdef __sparcv9 84 long double _Complex 85 _Q_cplx_mul(const long double _Complex *z, const long double _Complex *w) 86 { 87 long double _Complex v = 0; 88 #else 89 void 90 _Q_cplx_mul(long double _Complex *v, const long double _Complex *z, 91 const long double _Complex *w) 92 { 93 #endif 94 long double a, b, c, d, x, y; 95 int recalc, i, j; 96 97 /* 98 * The following is equivalent to 99 * 100 * a = creall(*z); b = cimagl(*z); 101 * c = creall(*w); d = cimagl(*w); 102 */ 103 a = ((long double *)z)[0]; 104 b = ((long double *)z)[1]; 105 c = ((long double *)w)[0]; 106 d = ((long double *)w)[1]; 107 108 x = a * c - b * d; 109 y = a * d + b * c; 110 111 if (x != x && y != y) { 112 /* 113 * Both x and y are NaN, so z and w can't both be finite. 114 * If at least one of z or w is a complex NaN, and neither 115 * is infinite, then we might as well deliver NaN + I * NaN. 116 * So the only cases to check are when one of z or w is 117 * infinite. 118 */ 119 recalc = 0; 120 i = testinfl(a); 121 j = testinfl(b); 122 if (i | j) { /* z is infinite */ 123 /* "factor out" infinity */ 124 a = i; 125 b = j; 126 recalc = 1; 127 } 128 i = testinfl(c); 129 j = testinfl(d); 130 if (i | j) { /* w is infinite */ 131 /* "factor out" infinity */ 132 c = i; 133 d = j; 134 recalc = 1; 135 } 136 if (recalc) { 137 x = inf.q * (a * c - b * d); 138 y = inf.q * (a * d + b * c); 139 } 140 } 141 142 #ifdef __sparcv9 143 ((long double *)&v)[0] = x; 144 ((long double *)&v)[1] = y; 145 return (v); 146 #else 147 ((long double *)v)[0] = x; 148 ((long double *)v)[1] = y; 149 #endif 150 } 151