mirror of
https://github.com/eried/portapack-mayhem.git
synced 2024-09-20 08:05:44 +00:00
143 lines
4.4 KiB
C++
143 lines
4.4 KiB
C++
/*
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* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
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* Copyright (C) 2017 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_siggen.hpp"
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#include "portapack_shared_memory.hpp"
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#include "sine_table_int8.hpp"
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#include "event_m4.hpp"
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#include <cstdint>
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void SigGenProcessor::execute(const buffer_c8_t& buffer) {
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if (!configured) return;
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for (size_t i = 0; i < buffer.count; i++) {
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if (!sample_count && auto_off) {
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configured = false;
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txprogress_message.done = true;
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shared_memory.application_queue.push(txprogress_message);
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} else
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sample_count--;
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if (tone_shape == 0) {
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// CW
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re = 127;
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im = 0;
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} else {
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if (tone_shape == 1) {
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// Sine
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sample = (sine_table_i8[(tone_phase & 0xFF000000) >> 24]);
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} else if (tone_shape == 2) {
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// Triangle
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int8_t a = (tone_phase & 0xFF000000) >> 24;
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sample = (a & 0x80) ? ((a << 1) ^ 0xFF) - 0x80 : (a << 1) + 0x80;
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} else if (tone_shape == 3) {
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// Saw up
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sample = ((tone_phase & 0xFF000000) >> 24);
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} else if (tone_shape == 4) {
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// Saw down
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sample = ((tone_phase & 0xFF000000) >> 24) ^ 0xFF;
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} else if (tone_shape == 5) {
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// Square
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sample = (((tone_phase & 0xFF000000) >> 24) & 0x80) ? 127 : -128;
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} else if (tone_shape == 6) {
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// Noise generator, pseudo random noise generator, 16 bits linear-feedback shift register (LFSR) algorithm, variant Fibonacci.
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// https://en.wikipedia.org/wiki/Linear-feedback_shift_register
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// 16 bits LFSR .taps: 16, 15, 13, 4 ;feedback polynomial: x^16 + x^15 + x^13 + x^4 + 1
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// Periode 65535= 2^n-1, quite continuous .
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if (counter == 0) { // we slow down the shift register, because the pseudo random noise clock freq was too high for modulator.
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bit_16 = ((lfsr_16 >> 0) ^ (lfsr_16 >> 1) ^ (lfsr_16 >> 3) ^ (lfsr_16 >> 4) ^ ((lfsr_16 >> 12) & 1));
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lfsr_16 = (lfsr_16 >> 1) | (bit_16 << 15);
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sample = (lfsr_16 & 0x00FF); // main pseudo random noise generator.
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}
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if (counter == 5) { // after many empiric test, that combination mix of >>4 and >>5, gives a reasonable trade off white noise / good rf power level .
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sample = ((lfsr_16 & 0b0000111111110000) >> 4); // just changing the spectrum shape .
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}
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if (counter == 10) {
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sample = ((lfsr_16 & 0b0001111111100000) >> 5); // just changing the spectrum shape .
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}
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counter++;
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if (counter ==15) {
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counter=0;
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}
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}
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if (tone_shape < 6) { // we are in periodic signals, we need tone phases update.
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tone_phase += tone_delta;
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}
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// Do FM modulation
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delta = sample * fm_delta;
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phase += delta;
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sphase = phase + (64 << 24);
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re = (sine_table_i8[(sphase & 0xFF000000) >> 24]);
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im = (sine_table_i8[( phase & 0xFF000000) >> 24]);
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}
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buffer.p[i] = {re, im};
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}
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};
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void SigGenProcessor::on_message(const Message* const msg) {
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const auto message = *reinterpret_cast<const SigGenConfigMessage*>(msg);
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switch(msg->id) {
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case Message::ID::SigGenConfig:
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if (!message.bw) {
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configured = false;
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return;
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}
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if (message.duration) {
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sample_count = message.duration;
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auto_off = true;
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} else
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auto_off = false;
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fm_delta = message.bw * (0xFFFFFFULL / 1536000);
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tone_shape = message.shape;
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// lfsr = seed_value ; // Finally not used , init lfsr 8 bits.
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lfsr_16 = seed_value_16; // init lfsr 16 bits.
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configured = true;
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break;
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case Message::ID::SigGenTone:
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tone_delta = reinterpret_cast<const SigGenToneMessage*>(msg)->tone_delta;
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break;
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default:
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break;
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}
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}
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int main() {
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EventDispatcher event_dispatcher { std::make_unique<SigGenProcessor>() };
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event_dispatcher.run();
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return 0;
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}
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