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81 lines
1.9 KiB
C++
81 lines
1.9 KiB
C++
//
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// Oric.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 06/11/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#include "Oric.hpp"
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using namespace Storage::Tape::Oric;
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int Parser::get_next_byte(const std::shared_ptr<Storage::Tape::Tape> &tape, bool use_fast_encoding)
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{
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_use_fast_encoding = use_fast_encoding;
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_cycle_length = 0.0f;
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int result = 0;
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int bit_count = 0;
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while(bit_count < 10 && !tape->is_at_end())
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{
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SymbolType symbol = get_next_symbol(tape);
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if(!bit_count && symbol != SymbolType::Zero) continue;
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result |= ((symbol == SymbolType::One) ? 1 : 0) << bit_count;
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bit_count++;
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}
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// TODO: check parity
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return tape->is_at_end() ? -1 : (result >> 1);
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}
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void Parser::process_pulse(Storage::Tape::Tape::Pulse pulse)
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{
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const float length_threshold = 0.0003125f;
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bool wave_is_high = pulse.type == Storage::Tape::Tape::Pulse::High;
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bool did_change = (wave_is_high != _wave_was_high && _cycle_length > 0.0f);
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_cycle_length += pulse.length.get_float();
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if(did_change)
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{
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if(_cycle_length > 2.0 * length_threshold) push_wave(WaveType::Unrecognised);
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else push_wave(_cycle_length < length_threshold ? WaveType::Short : WaveType::Long);
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_cycle_length = 0.0f;
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_wave_was_high = wave_is_high;
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}
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}
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void Parser::inspect_waves(const std::vector<WaveType> &waves)
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{
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if(_use_fast_encoding)
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{
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if(waves.size() < 2) return;
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if(waves[0] == WaveType::Long && waves[1] != WaveType::Unrecognised)
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{
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push_symbol((waves[1] == WaveType::Long) ? SymbolType::Zero : SymbolType::One, 2);
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return;
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}
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}
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else
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{
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if(waves.size() < 16) return;
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#define CHECK_RUN(length, type, symbol) \
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if(waves.size() >= length)\
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{\
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size_t c;\
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for(c = 0; c < length; c++) if(waves[c] != type) break;\
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if(c == length)\
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{\
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push_symbol(symbol, 8);\
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return;\
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}\
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}
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CHECK_RUN(8, WaveType::Long, SymbolType::Zero);
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CHECK_RUN(16, WaveType::Short, SymbolType::One);
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#undef CHECK_RUN
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}
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remove_waves(1);
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}
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