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https://github.com/TomHarte/CLK.git
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Started working towards capturing everything there is to know about a file. CRC calculation appears to be flawed somehow at the moment.
This commit is contained in:
Thomas Harte
parent
6218f05b8c
commit
b3521ed187
@ -11,36 +11,33 @@
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using namespace StaticAnalyser::Acorn;
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struct TapeParser {
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float wave_lengths[4];
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int wave_length_pointer;
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TapeParser() : wave_length_pointer(0) {}
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TapeParser(const std::shared_ptr<Storage::Tape::Tape> &tape) : _wave_length_pointer(0), _tape(tape) {}
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int GetNextBit(const std::shared_ptr<Storage::Tape::Tape> &tape)
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int get_next_bit()
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{
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while(!tape->is_at_end())
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while(!_tape->is_at_end())
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{
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// skip any gaps
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Storage::Tape::Tape::Pulse next_pulse = tape->get_next_pulse();
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Storage::Tape::Tape::Pulse next_pulse = _tape->get_next_pulse();
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while(next_pulse.type == Storage::Tape::Tape::Pulse::Zero)
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{
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next_pulse = tape->get_next_pulse();
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next_pulse = _tape->get_next_pulse();
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}
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wave_lengths[wave_length_pointer] = next_pulse.length.get_float();
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wave_length_pointer++;
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_wave_lengths[_wave_length_pointer] = next_pulse.length.get_float();
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_wave_length_pointer++;
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// if first wave is too short or too long, drop it
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if(wave_lengths[0] < 1.0f / 4800.0f || wave_lengths[0] >= 5.0f / 4800.0f)
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if(_wave_lengths[0] < 1.0f / 4800.0f || _wave_lengths[0] >= 5.0f / 4800.0f)
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{
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rotate(1);
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continue;
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}
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// if first two waves add up to a correct-length cycle, pop them and this is a 0
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if(wave_length_pointer >= 2)
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if(_wave_length_pointer >= 2)
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{
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float length = wave_lengths[0] + wave_lengths[1];
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float length = _wave_lengths[0] + _wave_lengths[1];
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if(length >= 3.0f / 4800.0f && length < 5.0f / 4800.0f)
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{
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rotate(2);
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@ -49,70 +46,165 @@ struct TapeParser {
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}
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// if all four waves add up to a correct-length cycle, pop them and this is a 1
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if(wave_length_pointer >= 4)
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if(_wave_length_pointer == 4)
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{
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float length = wave_lengths[0] + wave_lengths[1] + wave_lengths[2] + wave_lengths[3];
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float length = _wave_lengths[0] + _wave_lengths[1] + _wave_lengths[2] + _wave_lengths[3];
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if(length >= 3.0f / 4800.0f && length < 5.0f / 4800.0f)
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{
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rotate(4);
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return 1;
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}
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else
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{
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rotate(1);
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}
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}
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}
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return 0;
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}
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int GetNextByte(const std::shared_ptr<Storage::Tape::Tape> &tape)
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int get_next_byte()
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{
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int value = 0;
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int c = 8;
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if(GetNextBit(tape)) return -1;
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if(get_next_bit())
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{
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_error_flag = true;
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return -1;
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}
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while(c--)
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{
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value = (value >> 1) | (GetNextBit(tape) << 7);
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value = (value >> 1) | (get_next_bit() << 7);
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}
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if(!GetNextBit(tape)) return -1;
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if(!get_next_bit())
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{
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_error_flag = true;
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return -1;
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}
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add_to_crc((uint8_t)value);
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return value;
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}
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int get_next_short()
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{
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int result = get_next_byte();
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result |= get_next_byte() << 8;
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return result;
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}
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int get_next_word()
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{
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int result = get_next_short();
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result |= get_next_short() << 8;
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return result;
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}
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void reset_error_flag()
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{
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_error_flag = false;
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}
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bool get_error_flag()
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{
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return _error_flag;
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}
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void reset_crc()
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{
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_crc = 0;
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}
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void add_to_crc(uint8_t value)
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{
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_crc ^= (uint16_t)value << 8;
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for(int c = 0; c < 8; c++)
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{
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uint16_t exclusive_or = (_crc&0x8000) ? 0x1021 : 0x0000;
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_crc = (uint16_t)(_crc << 1) ^ exclusive_or;
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}
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}
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uint16_t get_crc()
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{
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return _crc;
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}
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bool is_at_end()
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{
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return _tape->is_at_end();
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}
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private:
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void rotate(int places)
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{
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wave_length_pointer -= places;
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if(places < 4) memmove(wave_lengths, &wave_lengths[places], (size_t)(4 - places) * sizeof(float));
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_wave_length_pointer -= places;
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if(places < 4) memmove(_wave_lengths, &_wave_lengths[places], (size_t)(4 - places) * sizeof(float));
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}
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uint16_t _crc;
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bool _error_flag;
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float _wave_lengths[4];
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int _wave_length_pointer;
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std::shared_ptr<Storage::Tape::Tape> _tape;
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};
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std::unique_ptr<File> StaticAnalyser::Acorn::GetNextFile(const std::shared_ptr<Storage::Tape::Tape> &tape)
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static std::unique_ptr<File::Chunk> GetNextChunk(TapeParser &parser)
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{
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std::unique_ptr<File::Chunk> new_chunk(new File::Chunk);
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int shift_register = 0;
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TapeParser parser;
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#define shift() \
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shift_register = (shift_register >> 1) | (parser.GetNextBit(tape) << 9)
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shift_register = (shift_register >> 1) | (parser.get_next_bit() << 9)
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// find next area of high tone
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while(!tape->is_at_end() && (shift_register != 0x3ff))
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while(!parser.is_at_end() && (shift_register != 0x3ff))
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{
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shift();
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}
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// find next 0x2a (swallowing stop bit)
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while(!tape->is_at_end() && (shift_register != 0x254))
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while(!parser.is_at_end() && (shift_register != 0x254))
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{
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shift();
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}
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parser.reset_crc();
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parser.reset_error_flag();
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// read out name
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char name[10];
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int name_ptr = 0;
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while(!tape->is_at_end() && name_ptr < 10)
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while(!parser.is_at_end() && name_ptr < 10)
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{
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name[name_ptr] = (char)parser.GetNextByte(tape);
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name[name_ptr] = (char)parser.get_next_byte();
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if(!name[name_ptr]) break;
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name_ptr++;
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}
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// addresses
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new_chunk->load_address = (uint32_t)parser.get_next_word();
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new_chunk->execution_address = (uint32_t)parser.get_next_word();
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new_chunk->block_number = (uint16_t)parser.get_next_short();
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new_chunk->block_length = (uint16_t)parser.get_next_short();
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new_chunk->block_flag = (uint8_t)parser.get_next_byte();
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new_chunk->next_address = (uint32_t)parser.get_next_word();
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uint16_t calculated_crc = parser.get_crc();
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uint16_t stored_crc = (uint16_t)parser.get_next_short();
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printf("%04x v %04x", calculated_crc, stored_crc);
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return nullptr;
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}
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std::unique_ptr<File> StaticAnalyser::Acorn::GetNextFile(const std::shared_ptr<Storage::Tape::Tape> &tape)
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{
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TapeParser parser(tape);
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GetNextChunk(parser);
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return nullptr;
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}
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@ -9,6 +9,7 @@
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#ifndef StaticAnalyser_Acorn_Tape_hpp
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#define StaticAnalyser_Acorn_Tape_hpp
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#include <list>
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#include <memory>
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#include <string>
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#include <vector>
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@ -20,10 +21,25 @@ namespace Acorn {
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struct File {
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std::string name;
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uint16_t load_address;
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uint16_t execution_address;
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uint32_t load_address;
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uint32_t execution_address;
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bool is_protected;
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std::vector<uint8_t> data;
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struct Chunk {
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uint32_t load_address;
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uint32_t execution_address;
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uint16_t block_number;
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uint16_t block_length;
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uint8_t block_flag;
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uint32_t next_address;
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bool header_crc_matched;
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bool data_crc_matched;
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std::vector<uint8_t> data;
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};
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std::list<Chunk> chunks;
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};
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std::unique_ptr<File> GetNextFile(const std::shared_ptr<Storage::Tape::Tape> &tape);
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