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89 lines
2.9 KiB
C
89 lines
2.9 KiB
C
/*-
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* Copyright (c) 2011 David Schultz <das@FreeBSD.ORG>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "cdefs-compat.h"
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//__FBSDID("$FreeBSD: src/lib/msun/src/s_cexp.c,v 1.3 2011/10/21 06:27:56 das Exp $");
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#include <openlibm_complex.h>
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#include <openlibm_math.h>
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#include "math_private.h"
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static const u_int32_t
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exp_ovfl = 0x40862e42, /* high bits of MAX_EXP * ln2 ~= 710 */
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cexp_ovfl = 0x4096b8e4; /* (MAX_EXP - MIN_DENORM_EXP) * ln2 */
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OLM_DLLEXPORT double complex
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cexp(double complex z)
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{
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double x, y, exp_x;
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u_int32_t hx, hy, lx, ly;
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x = creal(z);
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y = cimag(z);
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EXTRACT_WORDS(hy, ly, y);
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hy &= 0x7fffffff;
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/* cexp(x + I 0) = exp(x) + I 0 */
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if ((hy | ly) == 0)
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return (CMPLX(exp(x), y));
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EXTRACT_WORDS(hx, lx, x);
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/* cexp(0 + I y) = cos(y) + I sin(y) */
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if (((hx & 0x7fffffff) | lx) == 0)
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return (CMPLX(cos(y), sin(y)));
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if (hy >= 0x7ff00000) {
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if (lx != 0 || (hx & 0x7fffffff) != 0x7ff00000) {
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/* cexp(finite|NaN +- I Inf|NaN) = NaN + I NaN */
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return (CMPLX(y - y, y - y));
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} else if (hx & 0x80000000) {
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/* cexp(-Inf +- I Inf|NaN) = 0 + I 0 */
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return (CMPLX(0.0, 0.0));
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} else {
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/* cexp(+Inf +- I Inf|NaN) = Inf + I NaN */
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return (CMPLX(x, y - y));
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}
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}
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if (hx >= exp_ovfl && hx <= cexp_ovfl) {
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/*
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* x is between 709.7 and 1454.3, so we must scale to avoid
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* overflow in exp(x).
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*/
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return (__ldexp_cexp(z, 0));
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} else {
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/*
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* Cases covered here:
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* - x < exp_ovfl and exp(x) won't overflow (common case)
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* - x > cexp_ovfl, so exp(x) * s overflows for all s > 0
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* - x = +-Inf (generated by exp())
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* - x = NaN (spurious inexact exception from y)
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*/
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exp_x = exp(x);
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return (CMPLX(exp_x * cos(y), exp_x * sin(y)));
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}
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}
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