mirror of
https://github.com/TomHarte/CLK.git
synced 2024-08-29 11:29:52 +00:00
344 lines
8.1 KiB
C++
344 lines
8.1 KiB
C++
//
|
|
// TapeUEF.cpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 18/01/2016.
|
|
// Copyright 2016 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#include "TapeUEF.hpp"
|
|
#include <cstring>
|
|
#include <cstdio>
|
|
#include <cstdlib>
|
|
#include <cmath>
|
|
|
|
#define LOG_PREFIX "[UEF] "
|
|
#include "../../../Outputs/Log.hpp"
|
|
|
|
// MARK: - ZLib extensions
|
|
|
|
static float gzgetfloat(gzFile file) {
|
|
uint8_t bytes[4];
|
|
gzread(file, bytes, 4);
|
|
|
|
/* assume a four byte array named Float exists, where Float[0]
|
|
was the first byte read from the UEF, Float[1] the second, etc */
|
|
|
|
/* decode mantissa */
|
|
int mantissa;
|
|
mantissa = bytes[0] | (bytes[1] << 8) | ((bytes[2]&0x7f)|0x80) << 16;
|
|
|
|
float result = float(mantissa);
|
|
result = float(ldexp(result, -23));
|
|
|
|
/* decode exponent */
|
|
int exponent;
|
|
exponent = ((bytes[2]&0x80) >> 7) | (bytes[3]&0x7f) << 1;
|
|
exponent -= 127;
|
|
result = float(ldexp(result, exponent));
|
|
|
|
/* flip sign if necessary */
|
|
if(bytes[3]&0x80)
|
|
result = -result;
|
|
|
|
return result;
|
|
}
|
|
|
|
static uint8_t gzget8(gzFile file) {
|
|
// This is a workaround for gzgetc, which seems to be broken in ZLib 1.2.8.
|
|
uint8_t result;
|
|
gzread(file, &result, 1);
|
|
return result;
|
|
}
|
|
|
|
static int gzget16(gzFile file) {
|
|
uint8_t bytes[2];
|
|
gzread(file, bytes, 2);
|
|
return bytes[0] | (bytes[1] << 8);
|
|
}
|
|
|
|
static int gzget24(gzFile file) {
|
|
uint8_t bytes[3];
|
|
gzread(file, bytes, 3);
|
|
return bytes[0] | (bytes[1] << 8) | (bytes[2] << 16);
|
|
}
|
|
|
|
static int gzget32(gzFile file) {
|
|
uint8_t bytes[4];
|
|
gzread(file, bytes, 4);
|
|
return bytes[0] | (bytes[1] << 8) | (bytes[2] << 16) | (bytes[3] << 24);
|
|
}
|
|
|
|
using namespace Storage::Tape;
|
|
|
|
UEF::UEF(const std::string &file_name) {
|
|
file_ = gzopen(file_name.c_str(), "rb");
|
|
|
|
char identifier[10];
|
|
int bytes_read = gzread(file_, identifier, 10);
|
|
if(bytes_read < 10 || std::strcmp(identifier, "UEF File!")) {
|
|
throw ErrorNotUEF;
|
|
}
|
|
|
|
uint8_t version[2];
|
|
gzread(file_, version, 2);
|
|
|
|
if(version[1] > 0 || version[0] > 10) {
|
|
throw ErrorNotUEF;
|
|
}
|
|
|
|
set_platform_type();
|
|
}
|
|
|
|
UEF::~UEF() {
|
|
gzclose(file_);
|
|
}
|
|
|
|
// MARK: - Public methods
|
|
|
|
void UEF::virtual_reset() {
|
|
gzseek(file_, 12, SEEK_SET);
|
|
set_is_at_end(false);
|
|
clear();
|
|
}
|
|
|
|
// MARK: - Chunk navigator
|
|
|
|
bool UEF::get_next_chunk(UEF::Chunk &result) {
|
|
const uint16_t chunk_id = uint16_t(gzget16(file_));
|
|
const uint32_t chunk_length = uint32_t(gzget32(file_));
|
|
const z_off_t start_of_next_chunk = gztell(file_) + chunk_length;
|
|
|
|
if(gzeof(file_)) {
|
|
return false;
|
|
}
|
|
|
|
result.id = chunk_id;
|
|
result.length = chunk_length;
|
|
result.start_of_next_chunk = start_of_next_chunk;
|
|
|
|
return true;
|
|
}
|
|
|
|
void UEF::get_next_pulses() {
|
|
while(empty()) {
|
|
// read chunk details
|
|
Chunk next_chunk;
|
|
if(!get_next_chunk(next_chunk)) {
|
|
set_is_at_end(true);
|
|
return;
|
|
}
|
|
|
|
switch(next_chunk.id) {
|
|
case 0x0100: queue_implicit_bit_pattern(next_chunk.length); break;
|
|
case 0x0102: queue_explicit_bit_pattern(next_chunk.length); break;
|
|
case 0x0112: queue_integer_gap(); break;
|
|
case 0x0116: queue_floating_point_gap(); break;
|
|
|
|
case 0x0110: queue_carrier_tone(); break;
|
|
case 0x0111: queue_carrier_tone_with_dummy(); break;
|
|
|
|
case 0x0114: queue_security_cycles(); break;
|
|
case 0x0104: queue_defined_data(next_chunk.length); break;
|
|
|
|
// change of base rate
|
|
case 0x0113: {
|
|
// TODO: something smarter than just converting this to an int
|
|
const float new_time_base = gzgetfloat(file_);
|
|
time_base_ = unsigned(roundf(new_time_base));
|
|
}
|
|
break;
|
|
|
|
case 0x0117: {
|
|
const int baud_rate = gzget16(file_);
|
|
is_300_baud_ = (baud_rate == 300);
|
|
}
|
|
break;
|
|
|
|
default:
|
|
LOG("Skipping chunk of type " << PADHEX(4) << next_chunk.id);
|
|
break;
|
|
}
|
|
|
|
gzseek(file_, next_chunk.start_of_next_chunk, SEEK_SET);
|
|
}
|
|
}
|
|
|
|
// MARK: - Chunk parsers
|
|
|
|
void UEF::queue_implicit_bit_pattern(uint32_t length) {
|
|
while(length--) {
|
|
queue_implicit_byte(gzget8(file_));
|
|
}
|
|
}
|
|
|
|
void UEF::queue_explicit_bit_pattern(uint32_t length) {
|
|
const std::size_t length_in_bits = (length << 3) - size_t(gzget8(file_));
|
|
uint8_t current_byte = 0;
|
|
for(std::size_t bit = 0; bit < length_in_bits; bit++) {
|
|
if(!(bit&7)) current_byte = gzget8(file_);
|
|
queue_bit(current_byte&1);
|
|
current_byte >>= 1;
|
|
}
|
|
}
|
|
|
|
void UEF::queue_integer_gap() {
|
|
Time duration;
|
|
duration.length = unsigned(gzget16(file_));
|
|
duration.clock_rate = time_base_;
|
|
emplace_back(Pulse::Zero, duration);
|
|
}
|
|
|
|
void UEF::queue_floating_point_gap() {
|
|
const float length = gzgetfloat(file_);
|
|
Time duration;
|
|
duration.length = unsigned(length * 4000000);
|
|
duration.clock_rate = 4000000;
|
|
emplace_back(Pulse::Zero, duration);
|
|
}
|
|
|
|
void UEF::queue_carrier_tone() {
|
|
unsigned int number_of_cycles = unsigned(gzget16(file_));
|
|
while(number_of_cycles--) queue_bit(1);
|
|
}
|
|
|
|
void UEF::queue_carrier_tone_with_dummy() {
|
|
unsigned int pre_cycles = unsigned(gzget16(file_));
|
|
unsigned int post_cycles = unsigned(gzget16(file_));
|
|
while(pre_cycles--) queue_bit(1);
|
|
queue_implicit_byte(0xaa);
|
|
while(post_cycles--) queue_bit(1);
|
|
}
|
|
|
|
void UEF::queue_security_cycles() {
|
|
int number_of_cycles = gzget24(file_);
|
|
bool first_is_pulse = gzget8(file_) == 'P';
|
|
bool last_is_pulse = gzget8(file_) == 'P';
|
|
|
|
uint8_t current_byte = 0;
|
|
for(int cycle = 0; cycle < number_of_cycles; cycle++) {
|
|
if(!(cycle&7)) current_byte = gzget8(file_);
|
|
int bit = (current_byte >> 7);
|
|
current_byte <<= 1;
|
|
|
|
Time duration;
|
|
duration.length = bit ? 1 : 2;
|
|
duration.clock_rate = time_base_ * 4;
|
|
|
|
if(!cycle && first_is_pulse) {
|
|
emplace_back(Pulse::High, duration);
|
|
} else if(cycle == number_of_cycles-1 && last_is_pulse) {
|
|
emplace_back(Pulse::Low, duration);
|
|
} else {
|
|
emplace_back(Pulse::Low, duration);
|
|
emplace_back(Pulse::High, duration);
|
|
}
|
|
}
|
|
}
|
|
|
|
void UEF::queue_defined_data(uint32_t length) {
|
|
if(length < 3) return;
|
|
|
|
const int bits_per_packet = gzget8(file_);
|
|
const char parity_type = char(gzget8(file_));
|
|
int number_of_stop_bits = gzget8(file_);
|
|
|
|
const bool has_extra_stop_wave = (number_of_stop_bits < 0);
|
|
number_of_stop_bits = abs(number_of_stop_bits);
|
|
|
|
length -= 3;
|
|
while(length--) {
|
|
uint8_t byte = gzget8(file_);
|
|
|
|
uint8_t parity_value = byte;
|
|
parity_value ^= (parity_value >> 4);
|
|
parity_value ^= (parity_value >> 2);
|
|
parity_value ^= (parity_value >> 1);
|
|
|
|
queue_bit(0);
|
|
int c = bits_per_packet;
|
|
while(c--) {
|
|
queue_bit(byte&1);
|
|
byte >>= 1;
|
|
}
|
|
|
|
switch(parity_type) {
|
|
default: break;
|
|
case 'E': queue_bit(parity_value&1); break;
|
|
case 'O': queue_bit((parity_value&1) ^ 1); break;
|
|
}
|
|
|
|
int stop_bits = number_of_stop_bits;
|
|
while(stop_bits--) queue_bit(1);
|
|
if(has_extra_stop_wave) {
|
|
Time duration;
|
|
duration.length = 1;
|
|
duration.clock_rate = time_base_ * 4;
|
|
emplace_back(Pulse::Low, duration);
|
|
emplace_back(Pulse::High, duration);
|
|
}
|
|
}
|
|
}
|
|
|
|
// MARK: - Queuing helpers
|
|
|
|
void UEF::queue_implicit_byte(uint8_t byte) {
|
|
queue_bit(0);
|
|
int c = 8;
|
|
while(c--) {
|
|
queue_bit(byte&1);
|
|
byte >>= 1;
|
|
}
|
|
queue_bit(1);
|
|
}
|
|
|
|
void UEF::queue_bit(int bit) {
|
|
int number_of_cycles;
|
|
Time duration;
|
|
duration.clock_rate = time_base_ * 4;
|
|
|
|
if(bit) {
|
|
// encode high-frequency waves
|
|
duration.length = 1;
|
|
number_of_cycles = 2;
|
|
} else {
|
|
// encode low-frequency waves
|
|
duration.length = 2;
|
|
number_of_cycles = 1;
|
|
}
|
|
|
|
if(is_300_baud_) number_of_cycles *= 4;
|
|
|
|
while(number_of_cycles--) {
|
|
emplace_back(Pulse::Low, duration);
|
|
emplace_back(Pulse::High, duration);
|
|
}
|
|
}
|
|
|
|
// MARK: - TypeDistinguisher
|
|
|
|
TargetPlatform::Type UEF::target_platform_type() {
|
|
return platform_type_;
|
|
}
|
|
|
|
void UEF::set_platform_type() {
|
|
// If a chunk of type 0005 exists anywhere in the UEF then the UEF specifies its target machine.
|
|
// So check and, if so, update the list of machines for which this file thinks it is suitable.
|
|
Chunk next_chunk;
|
|
while(get_next_chunk(next_chunk)) {
|
|
if(next_chunk.id == 0x0005) {
|
|
uint8_t target = gzget8(file_);
|
|
switch(target >> 4) {
|
|
case 0: platform_type_ = TargetPlatform::BBCModelA; break;
|
|
case 1: platform_type_ = TargetPlatform::AcornElectron; break;
|
|
case 2: platform_type_ = TargetPlatform::BBCModelB; break;
|
|
case 3: platform_type_ = TargetPlatform::BBCMaster; break;
|
|
case 4: platform_type_ = TargetPlatform::AcornAtom; break;
|
|
default: break;
|
|
}
|
|
}
|
|
gzseek(file_, next_chunk.start_of_next_chunk, SEEK_SET);
|
|
}
|
|
reset();
|
|
}
|