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121 lines
3.9 KiB
C++
121 lines
3.9 KiB
C++
//
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// MFM.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 18/09/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#ifndef Storage_Disk_Encodings_MFM_hpp
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#define Storage_Disk_Encodings_MFM_hpp
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#include <cstdint>
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#include <vector>
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#include "../Disk.hpp"
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#include "../DiskController.hpp"
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#include "../../../NumberTheory/CRC.hpp"
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namespace Storage {
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namespace Encodings {
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namespace MFM {
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const uint8_t IndexAddressByte = 0xfc;
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const uint8_t IDAddressByte = 0xfe;
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const uint8_t DataAddressByte = 0xfb;
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const uint8_t DeletedDataAddressByte = 0xf8;
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const uint16_t FMIndexAddressMark = 0xf77a; // data 0xfc, with clock 0xd7 => 1111 1100 with clock 1101 0111 => 1111 0111 0111 1010
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const uint16_t FMIDAddressMark = 0xf57e; // data 0xfe, with clock 0xc7 => 1111 1110 with clock 1100 0111 => 1111 0101 0111 1110
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const uint16_t FMDataAddressMark = 0xf56f; // data 0xfb, with clock 0xc7 => 1111 1011 with clock 1100 0111 => 1111 0101 0110 1111
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const uint16_t FMDeletedDataAddressMark = 0xf56a; // data 0xf8, with clock 0xc7 => 1111 1000 with clock 1100 0111 => 1111 0101 0110 1010
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const uint16_t MFMIndexSync = 0x5224; // data 0xc2, with a missing clock at 0x0080 => 0101 0010 1010 0100 without 1000 0000
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const uint16_t MFMSync = 0x4489; // data 0xa1, with a missing clock at 0x0020 => 0100 0100 1010 1001 without 0010 0000
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const uint16_t MFMPostSyncCRCValue = 0xcdb4; // the value the CRC generator should have after encountering three 0xa1s
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const uint8_t MFMIndexSyncByteValue = 0xc2;
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const uint8_t MFMSyncByteValue = 0xa1;
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struct Sector {
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uint8_t track, side, sector;
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std::vector<uint8_t> data;
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};
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std::shared_ptr<Storage::Disk::Track> GetMFMTrackWithSectors(const std::vector<Sector> §ors);
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std::shared_ptr<Storage::Disk::Track> GetFMTrackWithSectors(const std::vector<Sector> §ors);
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class Encoder {
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public:
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Encoder(std::vector<uint8_t> &target);
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virtual void add_byte(uint8_t input) = 0;
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virtual void add_index_address_mark() = 0;
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virtual void add_ID_address_mark() = 0;
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virtual void add_data_address_mark() = 0;
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virtual void add_deleted_data_address_mark() = 0;
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virtual void output_short(uint16_t value);
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void add_crc();
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protected:
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NumberTheory::CRC16 crc_generator_;
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private:
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std::vector<uint8_t> &target_;
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};
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std::unique_ptr<Encoder> GetMFMEncoder(std::vector<uint8_t> &target);
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std::unique_ptr<Encoder> GetFMEncoder(std::vector<uint8_t> &target);
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class Parser: public Storage::Disk::Controller {
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public:
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Parser(bool is_mfm, const std::shared_ptr<Storage::Disk::Disk> &disk);
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Parser(bool is_mfm, const std::shared_ptr<Storage::Disk::Track> &track);
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/*!
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Attempts to read the sector located at @c track and @c sector.
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@returns a sector if one was found; @c nullptr otherwise.
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*/
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std::shared_ptr<Storage::Encodings::MFM::Sector> get_sector(uint8_t track, uint8_t sector);
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/*!
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Attempts to read the track at @c track, starting from the index hole.
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Decodes data bits only; clocks are omitted. Synchronisation values begin a new
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byte. If a synchronisation value begins partway through a byte then
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synchronisation-contributing bits will appear both in the preceding byte and
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in the next.
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@returns a vector of data found.
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*/
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std::vector<uint8_t> get_track(uint8_t track);
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private:
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Parser(bool is_mfm);
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std::shared_ptr<Storage::Disk::Drive> drive;
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unsigned int shift_register_;
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int index_count_;
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uint8_t track_;
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int bit_count_;
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NumberTheory::CRC16 crc_generator_;
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bool is_mfm_;
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void seek_to_track(uint8_t track);
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void process_input_bit(int value, unsigned int cycles_since_index_hole);
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void process_index_hole();
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uint8_t get_next_byte();
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uint8_t get_byte_for_shift_value(uint16_t value);
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std::shared_ptr<Storage::Encodings::MFM::Sector> get_next_sector();
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std::shared_ptr<Storage::Encodings::MFM::Sector> get_sector(uint8_t sector);
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std::vector<uint8_t> get_track();
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};
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}
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}
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}
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#endif /* MFM_hpp */
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