48 lines
1.7 KiB
C++
48 lines
1.7 KiB
C++
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/*
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* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
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*
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* This file is part of PortaPack.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef __UTILITY_M4_H__
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#define __UTILITY_M4_H__
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#if defined(LPC43XX_M4)
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#include <hal.h>
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static inline complex32_t multiply_conjugate_s16_s32(const complex16_t::rep_type a, const complex16_t::rep_type b) {
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// conjugate: conj(a + bj) = a - bj
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// multiply: (a + bj) * (c + dj) = (ac - bd) + (bc + ad)j
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// conjugate-multiply: (ac + bd) + (bc - ad)j
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//return { a.real() * b.real() + a.imag() * b.imag(), a.imag() * b.real() - a.real() * b.imag() };
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// NOTE: Did not use combination of SMUAD and SMUSDX because of non-saturating arithmetic.
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// const int32_t r = __SMUAD(a, b);
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// const int32_t i = __SMUSDX(b, a);
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const int32_t rr = __SMULBB(a, b);
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const int32_t ii = __SMULTT(a, b);
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const int32_t r = __QADD(rr, ii);
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const int32_t ir = __SMULTB(a, b);
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const int32_t ri = __SMULBT(a, b);
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const int32_t i = __QSUB(ir, ri);
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return { r, i };
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}
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#endif /* defined(LPC43XX_M4) */
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#endif/*__UTILITY_M4_H__*/
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