looper/backends/playback/zsm/zsm_backend.cpp

373 lines
13 KiB
C++

#include "zsm_backend.hpp"
#include <algorithm>
extern "C" {
#include "x16emu/glue.h"
#include "x16emu/vera_pcm.h"
#include "x16emu/vera_psg.h"
#include "x16emu/ymglue.h"
}
#include <exception>
#include <filesystem>
#include "file_backend.hpp"
#include <stddef.h>
#include <string.h>
#include <file_backend.hpp>
#define HZ (AUDIO_SAMPLERATE)
#define BUFFERS 32
void ZsmBackend::load(const char *filename) {
memset(&spec, 0, sizeof(spec));
spec.format = AUDIO_S16SYS;
spec.samples = 100;
spec.channels = 2;
spec.freq = PSG_FREQ;
spec.size = 100 * 2 * sizeof(int16_t);
file = open_file(filename);
char magic[2];
file->read(magic, 2, 1);
if (magic[0] != 0x7a || magic[1] != 0x6d) {
throw std::exception();
}
uint8_t version;
file->read(&version, 1, 1);
uint8_t loop_point[3];
file->read(loop_point, 3, 1);
this->loop_point = loop_point[0] | ((uint32_t)(loop_point[1]) << 8) | ((uint32_t)(loop_point[2]) << 16);
file->read(loop_point, 3, 1);
this->pcm_offset = loop_point[0] | ((uint32_t)(loop_point[1]) << 8) | ((uint32_t)(loop_point[2]) << 16);
pcm_offset += 3;
file->read(&fm_mask, 1, 1);
file->read(loop_point, 2, 1);
this->psg_channel_mask = loop_point[0] | ((uint16_t)(loop_point[1]) << 8);
file->read(loop_point, 2, 1);
this->tick_rate = loop_point[0] | ((uint16_t)(loop_point[1]) << 8);
file->read(loop_point, 2, 1); // Reserved.
music_data_start = file->get_pos();
this->loop_point += music_data_start;
file->seek(pcm_offset, SeekType::SET);
file->read(loop_point, 1, 1);
pcm_offset++;
pcm_data_offs = ((((uint16_t)loop_point[0]) + 1) * 16) + pcm_offset;
file->seek(music_data_start, SeekType::SET);
this->loop_point = std::max(this->loop_point, (uint32_t)music_data_start);
double prev_time = 0.0;
double time = 0.0;
double tmpDelayTicks = 0.0;
loop_pos = -1.0;
uint32_t prev_pos = music_data_start;
while (true) {
tmpDelayTicks -= get_delay_per_frame();
if (tmpDelayTicks < 0.0) {
ZsmCommand cmd = get_command();
size_t cur_pos = file->get_pos();
if (cur_pos >= this->loop_point && this->loop_pos < 0) {
loop_pos = time;
this->loop_point = cur_pos;
}
if (cmd.id == ZsmEOF) {
break;
} else if (cmd.id == Delay) {
time += ((double)cmd.delay) / ((double)(tick_rate));
tmpDelayTicks += cmd.delay;
}
prev_pos = file->get_pos();
prev_time = time;
}
}
if (this->loop_pos < 0.0) {
this->loop_pos = 0.0;
this->loop_point = music_data_start;
}
length = time;
music_data_len = file->get_pos();
switch_stream(0);
loop_end = length;
loop_start = this->loop_pos;
fm_stream = SDL_NewAudioStream(AUDIO_S16SYS, 2, YM_FREQ, AUDIO_S16SYS, 2, PSG_FREQ);
DEBUG.writefln("fm_stream: %ld -> %ld", YM_FREQ, PSG_FREQ);
}
extern SDL_AudioSpec obtained;
void ZsmBackend::switch_stream(int idx) {
YM_Create(YM_FREQ);
YM_init(YM_FREQ/64, 60);
YM_reset();
psg_reset();
pcm_reset();
for (uint8_t i = 0; i < 16; i++) {
psg_writereg(i * 4 + 2, 0);
}
this->cpuClocks = 0.0;
this->delayTicks = 0.0;
this->ticks = 0.0;
}
void ZsmBackend::cleanup() {
delete file;
file = nullptr;
audio_buf.clear();
SDL_FreeAudioStream(fm_stream);
fm_stream = nullptr;
}
void ZsmBackend::tick(bool step) {
delayTicks -= 1;
const double ClocksPerTick = ((double)HZ) / ((double)tick_rate);
double prevCpuClocks = cpuClocks;
double nextCpuClocks = cpuClocks + ClocksPerTick;
double ticks_remaining = ClocksPerTick;
while (delayTicks <= 0) {
ZsmCommand cmd = get_command();
switch (cmd.id) {
case ZsmEOF: {
if (step) {
file->seek(this->loop_point, SeekType::SET);
this->position = loop_pos;
} else {
throw std::exception();
}
} break;
case PsgWrite: {
psg_writereg(cmd.psg_write.reg, cmd.psg_write.val);
} break;
case FmWrite: {
for (uint8_t i = 0; i < cmd.fm_write.len; i++) {
YM_write_reg(cmd.fm_write.regs[i].reg, cmd.fm_write.regs[i].val);
while (YM_read_status()) {
size_t clocksToAddForYm = 64;
ticks_remaining -= clocksToAddForYm;
if (ticks_remaining < 0) {
delayTicks -= 1;
nextCpuClocks += ClocksPerTick;
ticks_remaining += ClocksPerTick;
}
audio_step(clocksToAddForYm);
}
}
} break;
case Delay: {
delayTicks += cmd.delay;
position += ((double)cmd.delay) / ((double)(tick_rate));
} break;
case ExtCmd: {
//cmd.extcmd.channel
switch (cmd.extcmd.channel) {
case 0: {
for (size_t i = 0; i < cmd.extcmd.bytes; i += 2) {
switch (cmd.extcmd.pcm[i]) {
case 0: { // ctrl
uint8_t ctrl = cmd.extcmd.pcm[i + 1];
if (ctrl & 0x80) {
remain = 0;
}
pcm_write_ctrl(ctrl);
} break;
case 1: { // rate
pcm_write_rate(cmd.extcmd.pcm[i + 1]);
} break;
default: { // trigger
size_t file_pos = file->get_pos();
uint8_t ctrl = pcm_read_ctrl();
pcm_write_ctrl(ctrl | 0x80);
uint16_t pcm_idx = cmd.extcmd.pcm[i + 1];
uint16_t instdef = pcm_idx * 16;
file->seek(pcm_offset + instdef, SeekType::SET);
uint8_t geom;
file->read(&geom, 1, 1);
ctrl = pcm_read_ctrl() & 0x0F;
ctrl |= geom & 0x30;
pcm_write_ctrl(ctrl);
uint8_t bytes[10];
file->read(bytes, 10, 1);
loop_rem = bytes[9];
loop_rem <<= 8;
loop_rem |= bytes[8];
loop_rem <<= 8;
loop_rem |= bytes[7];
loop = loop_rem;
islooped = bytes[6] & 0x80;
remain = bytes[5];
remain <<= 8;
remain |= bytes[4];
remain <<= 8;
remain |= bytes[3];
cur = bytes[2];
cur <<= 8;
cur |= bytes[1];
cur <<= 8;
cur |= bytes[0];
cur += pcm_data_offs;
loop += cur;
loop_rem = remain - loop_rem;
file->seek(file_pos, SeekType::SET);
} break;
}
//cmd.extcmd.pcm
audio_step(0);
} break;
}
// Nothing handled yet.
}
} break;
}
}
size_t nextCpuClocksInt = std::floor(nextCpuClocks);
size_t prevCpuClocksInt = std::floor(prevCpuClocks);
size_t cpuClocksIntDelta = nextCpuClocksInt - prevCpuClocksInt;
audio_step(cpuClocksIntDelta);
cpuClocks = std::fmod(nextCpuClocks, ClocksPerTick);
}
size_t ZsmBackend::render(void *buf, size_t maxlen) {
size_t sample_type_len = 2;
maxlen /= sample_type_len;
while (audio_buf.size() <= maxlen) {
tick(true);
}
size_t copied = copy_out(buf, maxlen) * sample_type_len;
maxlen *= sample_type_len;
return copied;
}
uint64_t ZsmBackend::get_min_samples() {
return spec.size;
}
std::optional<uint64_t> ZsmBackend::get_max_samples() {
return get_min_samples();
}
ZsmCommand ZsmBackend::get_command() {
ZsmCommandId cmdid;
uint8_t cmd_byte;
file->read(&cmd_byte, 1, 1);
if (cmd_byte == 0x80) {
cmdid = ZsmEOF;
} else {
if ((cmd_byte >> 6) == 0) {
cmdid = PsgWrite;
} else if ((cmd_byte >> 6) == 0b01) {
if (cmd_byte == 0b01000000) {
cmdid = ExtCmd;
} else {
cmdid = FmWrite;
}
} else {
cmdid = Delay;
}
}
ZsmCommand output;
output.id = cmdid;
if (cmdid == ZsmEOF) {
return output;
} else if (cmdid == PsgWrite) {
uint8_t value;
file->read(&value, 1, 1);
output.psg_write.reg = cmd_byte & 0x3F;
output.psg_write.val = value;
} else if (cmdid == FmWrite) {
uint16_t _value;
uint8_t *value = (uint8_t*)(void*)(&_value);
uint8_t pairs = cmd_byte & 0b111111;
output.fm_write.len = pairs;
output.fm_write.regs = (reg_pair*)malloc((sizeof(reg_pair))*pairs);
for (uint8_t i = 0; i < pairs; i++) {
file->read(value, 2, 1);
output.fm_write.regs[i].reg = value[0];
output.fm_write.regs[i].val = value[1];
}
} else if (cmdid == ExtCmd) {
uint8_t ext_cmd_byte;
file->read(&ext_cmd_byte, 1, 1);
uint8_t bytes = ext_cmd_byte & 0x3F;
uint8_t ch = ext_cmd_byte >> 6;
output.extcmd.channel = ch;
output.extcmd.bytes = bytes;
if (ch == 1) {
output.extcmd.expansion.write_bytes = NULL;
} else {
output.extcmd.pcm = (uint8_t*)malloc(bytes); // Handles all other cases due to them being in a union, and each having the same type.
}
for (size_t i = 0; i < bytes; i++) {
uint8_t byte;
file->read(&byte, 1, 1);
switch (ch) {
case 0: {
output.extcmd.pcm[i] = byte;
} break;
case 1: {
if (i == 0) {
output.extcmd.expansion.chip_id = byte;
} else if (i == 1) {
output.extcmd.expansion.writes = byte;
output.extcmd.expansion.write_bytes = (uint8_t*)malloc(byte);
} else {
output.extcmd.expansion.write_bytes[i - 2] = byte;
}
} break;
case 2: {
output.extcmd.sync[i] = byte;
} break;
case 3: {
output.extcmd.custom[i] = byte;
} break;
}
}
} else if (cmdid == Delay) {
output.delay = cmd_byte & 0x7F;
}
return output;
}
ZsmCommand::~ZsmCommand() {
switch (id) {
case ExtCmd: {
if (extcmd.channel == 1) {
if (extcmd.expansion.write_bytes != NULL) {
free(extcmd.expansion.write_bytes);
}
} else {
free(extcmd.pcm);
}
} break;
case FmWrite: {
free(fm_write.regs);
}
}
}
void ZsmBackend::seek_internal(double position, bool loop) {
this->position = std::floor(this->position * PSG_FREQ) / PSG_FREQ;
position = std::floor(position * PSG_FREQ) / PSG_FREQ;
if (this->position > position) {
file->seek(music_data_start, SeekType::SET);
this->cpuClocks = 0.0;
this->delayTicks = 0;
this->ticks = 0.0;
this->position = 0.0;
} else if (this->position == position) {
audio_buf.clear();
return;
} else {
switch_stream(0);
}
while (this->position < position) {
audio_buf.clear();
try {
tick(false);
} catch (std::exception) {
switch_stream(0);
file->seek(music_data_start, SeekType::SET);
this->cpuClocks = 0.0;
this->delayTicks = 0;
this->ticks = 0.0;
this->position = 0.0;
audio_buf.clear();
return;
}
}
size_t samples = std::min((size_t)((this->position - position) * PSG_FREQ), audio_buf.size());
while (samples--) {
audio_buf.pop();
}
this->position = position;
}
void ZsmBackend::seek(double position) {
seek_internal(position, false);
}
double ZsmBackend::get_position() {
return position;
}
int ZsmBackend::get_stream_idx() {
return 0;
}