/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (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 2003 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ /* * On SPARC V8, _Q_cplx_div(v, z, w) sets *v = *z / *w with infin- * ities handling according to C99. * * On SPARC V9, _Q_cplx_div(z, w) returns *z / *w with infinities * handled according to C99. * * If z and w are both finite and w is nonzero, _Q_cplx_div delivers * the complex quotient q according to the usual formula: let a = * Re(z), b = Im(z), c = Re(w), and d = Im(w); then q = x + I * y * where x = (a * c + b * d) / r and y = (b * c - a * d) / r with * r = c * c + d * d. This implementation scales to avoid premature * underflow or overflow. * * If z is neither NaN nor zero and w is zero, or if z is infinite * and w is finite and nonzero, _Q_cplx_div delivers an infinite * result. If z is finite and w is infinite, _Q_cplx_div delivers * a zero result. * * If z and w are both zero or both infinite, or if either z or w is * a complex NaN, _Q_cplx_div delivers NaN + I * NaN. C99 doesn't * specify these cases. * * This implementation can raise spurious underflow, overflow, in- * valid operation, inexact, and division-by-zero exceptions. C99 * allows this. */ #if !defined(sparc) && !defined(__sparc) #error This code is for SPARC only #endif static union { int i[4]; long double q; } inf = { 0x7fff0000, 0, 0, 0 }; /* * Return +1 if x is +Inf, -1 if x is -Inf, and 0 otherwise */ static int testinfl(long double x) { union { int i[4]; long double q; } xx; xx.q = x; return (((((xx.i[0] << 1) - 0xfffe0000) | xx.i[1] | xx.i[2] | xx.i[3]) == 0)? (1 | (xx.i[0] >> 31)) : 0); } #ifdef __sparcv9 long double _Complex _Q_cplx_div(const long double _Complex *z, const long double _Complex *w) { long double _Complex v = 0; #else void _Q_cplx_div(long double _Complex *v, const long double _Complex *z, const long double _Complex *w) { #endif union { int i[4]; long double q; } aa, bb, cc, dd, ss; long double a, b, c, d, r; int ha, hb, hc, hd, hz, hw, hs, i, j; /* * The following is equivalent to * * a = creall(*z); b = cimagl(*z); * c = creall(*w); d = cimagl(*w); */ a = ((long double *)z)[0]; b = ((long double *)z)[1]; c = ((long double *)w)[0]; d = ((long double *)w)[1]; /* extract high-order words to estimate |z| and |w| */ aa.q = a; bb.q = b; ha = aa.i[0] & ~0x80000000; hb = bb.i[0] & ~0x80000000; hz = (ha > hb)? ha : hb; cc.q = c; dd.q = d; hc = cc.i[0] & ~0x80000000; hd = dd.i[0] & ~0x80000000; hw = (hc > hd)? hc : hd; /* check for special cases */ if (hw >= 0x7fff0000) { /* w is inf or nan */ r = 0.0l; i = testinfl(c); j = testinfl(d); if (i | j) { /* w is infinite */ /* * "factor out" infinity, being careful to preserve * signs of finite values */ c = i? i : ((cc.i[0] < 0)? -0.0l : 0.0l); d = j? j : ((dd.i[0] < 0)? -0.0l : 0.0l); if (hz >= 0x7ffe0000) { /* scale to avoid overflow below */ c *= 0.5l; d *= 0.5l; } } goto done; } if (hw == 0 && (cc.i[1] | cc.i[2] | cc.i[3] | dd.i[1] | dd.i[2] | dd.i[3]) == 0) { /* w is zero; multiply z by 1/Re(w) - I * Im(w) */ r = 1.0l; c = 1.0l / c; i = testinfl(a); j = testinfl(b); if (i | j) { /* z is infinite */ a = i; b = j; } goto done; } if (hz >= 0x7fff0000) { /* z is inf or nan */ r = 1.0l; i = testinfl(a); j = testinfl(b); if (i | j) { /* z is infinite */ a = i; b = j; r = inf.q; } goto done; } /* * Scale c and d to compute 1/|w|^2 and the real and imaginary * parts of the quotient. */ hs = (((hw >> 2) - hw) + 0x6ffd7fff) & 0xffff0000; if (hz < 0x00ea0000) { /* |z| < 2^-16149 */ if (((hw - 0x3e380000) | (0x40e90000 - hw)) >= 0) hs = (((0x40e90000 - hw) >> 1) & 0xffff0000) + 0x3fff0000; } ss.i[0] = hs; ss.i[1] = ss.i[2] = ss.i[3] = 0; c *= ss.q; d *= ss.q; r = 1.0l / (c * c + d * d); c *= ss.q; d *= ss.q; done: #ifdef __sparcv9 ((long double *)&v)[0] = (a * c + b * d) * r; ((long double *)&v)[1] = (b * c - a * d) * r; return (v); #else ((long double *)v)[0] = (a * c + b * d) * r; ((long double *)v)[1] = (b * c - a * d) * r; #endif }
