mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
synced 2024-12-14 20:18:13 +00:00
107 lines
2.2 KiB
C++
107 lines
2.2 KiB
C++
/*
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* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
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* Copyright (C) 2016 Furrtek
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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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#include "proc_audiotx.hpp"
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#include "portapack_shared_memory.hpp"
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#include "sine_table.hpp"
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#include "audio_output.hpp"
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#include "lfsr_random.hpp"
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#include <cstdint>
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uint32_t lfsr(uint32_t v) {
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enum {
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length = 31,
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tap_0 = 31,
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tap_1 = 18,
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shift_amount_0 = 12,
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shift_amount_1 = 12,
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shift_amount_2 = 8
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};
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const lfsr_word_t zero = 0;
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v = (
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(
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v << shift_amount_0
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) | (
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(
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(v >> (tap_0 - shift_amount_0)) ^
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(v >> (tap_1 - shift_amount_0))
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) & (
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~(~zero << shift_amount_0)
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)
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)
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);
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v = (
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(
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v << shift_amount_1
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) | (
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(
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(v >> (tap_0 - shift_amount_1)) ^
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(v >> (tap_1 - shift_amount_1))
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) & (
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~(~zero << shift_amount_1)
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)
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)
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);
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v = (
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(
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v << shift_amount_2
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) | (
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(
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(v >> (tap_0 - shift_amount_2)) ^
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(v >> (tap_1 - shift_amount_2))
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) & (
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~(~zero << shift_amount_2)
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)
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)
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);
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return v;
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}
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void AudioTXProcessor::execute(const buffer_c8_t& buffer){
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for (size_t i = 0; i<buffer.count; i++) {
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sample = (sine_table_f32[(aphase & 0x03FF0000)>>18]*127); //(int8_t)lfsr(sample + i);
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if (bc & 0x40)
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aphase += 60000;
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else
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aphase += 90000;
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//FM
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frq = sample * 2500;
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phase = (phase + frq);
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sphase = phase + (256<<16);
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re = (sine_table_f32[(sphase & 0x03FF0000)>>18]*127);
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im = (sine_table_f32[(phase & 0x03FF0000)>>18]*127);
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buffer.p[i] = {(int8_t)re,(int8_t)im};
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}
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bc++;
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}
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