portapack-mayhem/firmware/common/utility_m4.hpp

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