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103 lines
2.4 KiB
C++
103 lines
2.4 KiB
C++
//
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// ZX80O.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 04/06/2017.
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// Copyright © 2017 Thomas Harte. All rights reserved.
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//
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#include "ZX80O81P.hpp"
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#include "../../Data/ZX8081.hpp"
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using namespace Storage::Tape;
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ZX80O81P::ZX80O81P(const char *file_name) :
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Storage::FileHolder(file_name) {
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// Grab the actual file contents
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data_.resize((size_t)file_stats_.st_size);
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fread(data_.data(), 1, (size_t)file_stats_.st_size, file_);
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// If it's a ZX81 file, prepend a file name.
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char type = (char)tolower(file_name[strlen(file_name) - 1]);
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if(type == 'p' || type == '1') {
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// TODO, maybe: prefix a proper file name; this is leaving the file nameless.
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data_.insert(data_.begin(), 0x80);
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}
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std::shared_ptr<::Storage::Data::ZX8081::File> file = Storage::Data::ZX8081::FileFromData(data_);
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if(!file) throw ErrorNotZX80O81P;
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// then rewind and start again
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virtual_reset();
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}
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void ZX80O81P::virtual_reset() {
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data_pointer_ = 0;
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is_past_silence_ = false;
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has_ended_final_byte_ = false;
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is_high_ = true;
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bit_pointer_ = wave_pointer_ = 0;
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}
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bool ZX80O81P::has_finished_data() {
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return (data_pointer_ == data_.size()) && !wave_pointer_ && !bit_pointer_;
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}
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bool ZX80O81P::is_at_end() {
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return has_finished_data() && has_ended_final_byte_;
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}
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Tape::Pulse ZX80O81P::virtual_get_next_pulse() {
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Tape::Pulse pulse;
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// Start with 1 second of silence.
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if(!is_past_silence_ || has_finished_data()) {
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pulse.type = Pulse::Type::Low;
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pulse.length.length = 1;
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pulse.length.clock_rate = 1;
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is_past_silence_ = true;
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has_ended_final_byte_ = has_finished_data();
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return pulse;
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}
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// For each byte, output 8 bits and then silence.
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if(!bit_pointer_ && !wave_pointer_) {
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byte_ = data_[data_pointer_];
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data_pointer_++;
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bit_pointer_ = 0;
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wave_pointer_ = 0;
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}
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if(!wave_pointer_) {
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// post-waves silence (here actually a pre-waves silence) is 1300µs
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pulse.length.length = 13;
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pulse.length.clock_rate = 10000;
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pulse.type = Pulse::Type::Low;
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wave_pointer_ ++;
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} else {
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// pulses are of length 150µs
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pulse.length.length = 3;
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pulse.length.clock_rate = 20000;
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if(is_high_) {
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pulse.type = Pulse::Type::High;
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is_high_ = false;
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} else {
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pulse.type = Pulse::Type::Low;
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is_high_ = true;
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// Bytes are stored MSB first.
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int wave_count = (byte_ & (0x80 >> bit_pointer_)) ? 9 : 4;
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wave_pointer_++;
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if(wave_pointer_ == wave_count + 1) {
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bit_pointer_ = (bit_pointer_ + 1)&7;
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wave_pointer_ = 0;
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}
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}
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}
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return pulse;
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}
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