portapack-mayhem/firmware/baseband/proc_rds.cpp

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/*
* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
* Copyright (C) 2016 Furrtek
*
* 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.
*/
#include "proc_rds.hpp"
#include "portapack_shared_memory.hpp"
#include "sine_table_int8.hpp"
#include "event_m4.hpp"
#include <cstdint>
void RDSProcessor::execute(const buffer_c8_t& buffer) {
for (size_t i = 0; i < buffer.count; i++) {
// Sample generation at 2.28M / 10 = 228kHz
if (s >= 9) {
s = 0;
if (sample_count >= SAMPLES_PER_BIT) {
if (bit_pos >= message_length) {
bit_pos = 0;
cur_output = 0;
}
cur_bit = (rdsdata[(bit_pos / 26) & 127] >> (25 - (bit_pos % 26))) & 1;
prev_output = cur_output;
cur_output = prev_output ^ cur_bit;
const int32_t* src = waveform_biphase;
int idx = in_sample_index;
for (int j = 0; j < FILTER_SIZE; j++) {
val = (*src++);
if (cur_output) val = -val;
sample_buffer[idx++] += val;
if (idx >= SAMPLE_BUFFER_SIZE) idx = 0;
}
in_sample_index += SAMPLES_PER_BIT;
if (in_sample_index >= SAMPLE_BUFFER_SIZE) in_sample_index -= SAMPLE_BUFFER_SIZE;
bit_pos++;
sample_count = 0;
}
sample = sample_buffer[out_sample_index];
sample_buffer[out_sample_index] = 0;
out_sample_index++;
if (out_sample_index >= SAMPLE_BUFFER_SIZE) out_sample_index = 0;
// AM @ 228k/4 = 57kHz
// 0, sample, 0, -sample...
switch (mphase & 3) {
case 0:
case 2:
sample = 0;
break;
case 1:
break;
case 3:
sample = -sample; // break;
}
mphase++;
sample_count++;
} else {
s++;
}
// FM
delta = (sample >> 16) * 386760; // ?
phase += delta;
sphase = phase + (64 << 18);
re = (sine_table_i8[(sphase & 0x03FF0000) >> 18]);
im = (sine_table_i8[(phase & 0x03FF0000) >> 18]);
buffer.p[i] = {re, im};
}
}
void RDSProcessor::on_message(const Message* const msg) {
if (msg->id == Message::ID::RDSConfigure) {
const auto message = *reinterpret_cast<const RDSConfigureMessage*>(msg);
rdsdata = (uint32_t*)shared_memory.bb_data.data;
message_length = message.length;
configured = true;
}
}
int main() {
EventDispatcher event_dispatcher{std::make_unique<RDSProcessor>()};
event_dispatcher.run();
return 0;
}