mirror of
https://github.com/davidgiven/fluxengine.git
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Refactor the encoders the same way that's been done for the decoders.
This commit is contained in:
David Given
@@ -9,6 +9,7 @@
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#include "writer.h"
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#include "fmt/format.h"
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#include "arch/c64/c64.pb.h"
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#include "lib/encoders/encoders.pb.h"
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#include <ctype.h>
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#include "bytes.h"
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@@ -202,147 +203,167 @@ static std::vector<bool> encode_data(uint8_t input)
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return output;
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}
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void Commodore64Encoder::writeSector(std::vector<bool>& bits, unsigned& cursor, const Sector* sector) const
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class Commodore64Encoder : public AbstractEncoder
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{
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/* Source: http://www.unusedino.de/ec64/technical/formats/g64.html
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* 1. Header sync FF FF FF FF FF (40 'on' bits, not GCR)
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* 2. Header info 52 54 B5 29 4B 7A 5E 95 55 55 (10 GCR bytes)
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* 3. Header gap 55 55 55 55 55 55 55 55 55 (9 bytes, never read)
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* 4. Data sync FF FF FF FF FF (40 'on' bits, not GCR)
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* 5. Data block 55...4A (325 GCR bytes)
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* 6. Inter-sector gap 55 55 55 55...55 55 (4 to 12 bytes, never read)
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* 1. Header sync (SYNC for the next sector)
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*/
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if ((sector->status == Sector::OK) or (sector->status == Sector::BAD_CHECKSUM))
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public:
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Commodore64Encoder(const EncoderProto& config):
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AbstractEncoder(config),
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_config(config.c64())
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{}
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public:
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std::unique_ptr<Fluxmap> encode(int physicalTrack, int physicalSide, const SectorSet& allSectors)
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{
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// There is data to encode to disk.
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if ((sector->data.size() != C64_SECTOR_LENGTH))
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Error() << fmt::format("unsupported sector size {} --- you must pick 256", sector->data.size());
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/* The format ID Character # 1 and # 2 are in the .d64 image only present
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* in track 18 sector zero which contains the BAM info in byte 162 and 163.
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* it is written in every header of every sector and track. headers are not
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* stored in a d64 disk image so we have to get it from track 18 which
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* contains the BAM.
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*/
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// 1. Write header Sync (not GCR)
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for (int i=0; i<6; i++)
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write_bits(bits, cursor, C64_HEADER_DATA_SYNC, 1*8); /* sync */
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// 2. Write Header info 10 GCR bytes
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/*
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* The 10 byte header info (#2) is GCR encoded and must be decoded to
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* it's normal 8 bytes to be understood. Once decoded, its breakdown is
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* as follows:
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*
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* Byte $00 - header block ID ($08)
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* 01 - header block checksum 16 (EOR of $02-$05)
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* 02 - Sector
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* 03 - Track
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* 04 - Format ID byte #2
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* 05 - Format ID byte #1
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* 06-07 - $0F ("off" bytes)
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*/
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uint8_t encodedTrack = ((sector->logicalTrack) + 1); // C64 track numbering starts with 1. Fluxengine with 0.
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uint8_t encodedSector = sector->logicalSector;
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// uint8_t formatByte1 = C64_FORMAT_ID_BYTE1;
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// uint8_t formatByte2 = C64_FORMAT_ID_BYTE2;
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uint8_t headerChecksum = (encodedTrack ^ encodedSector ^ _formatByte1 ^ _formatByte2);
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write_bits(bits, cursor, encode_data(C64_HEADER_BLOCK_ID));
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write_bits(bits, cursor, encode_data(headerChecksum));
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write_bits(bits, cursor, encode_data(encodedSector));
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write_bits(bits, cursor, encode_data(encodedTrack));
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write_bits(bits, cursor, encode_data(_formatByte2));
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write_bits(bits, cursor, encode_data(_formatByte1));
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write_bits(bits, cursor, encode_data(C64_PADDING));
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write_bits(bits, cursor, encode_data(C64_PADDING));
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// 3. Write header GAP not GCR
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for (int i=0; i<9; i++)
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write_bits(bits, cursor, C64_HEADER_GAP, 1*8); /* header gap */
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// 4. Write Data sync not GCR
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for (int i=0; i<6; i++)
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write_bits(bits, cursor, C64_HEADER_DATA_SYNC, 1*8); /* sync */
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// 5. Write data block 325 GCR bytes
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/*
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* The 325 byte data block (#5) is GCR encoded and must be decoded to its
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* normal 260 bytes to be understood. The data block is made up of the following:
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*
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* Byte $00 - data block ID ($07)
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* 01-100 - 256 bytes data
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* 101 - data block checksum (EOR of $01-100)
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* 102-103 - $00 ("off" bytes, to make the sector size a multiple of 5)
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*/
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write_bits(bits, cursor, encode_data(C64_DATA_BLOCK_ID));
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uint8_t dataChecksum = xorBytes(sector->data);
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ByteReader br(sector->data);
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int i = 0;
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for (i = 0; i < C64_SECTOR_LENGTH; i++)
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{
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uint8_t val = br.read_8();
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write_bits(bits, cursor, encode_data(val));
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}
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write_bits(bits, cursor, encode_data(dataChecksum));
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write_bits(bits, cursor, encode_data(C64_PADDING));
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write_bits(bits, cursor, encode_data(C64_PADDING));
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//6. Write inter-sector gap 9 - 12 bytes nor gcr
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for (int i=0; i<9; i++)
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write_bits(bits, cursor, C64_INTER_SECTOR_GAP, 1*8); /* sync */
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}
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}
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std::unique_ptr<Fluxmap> Commodore64Encoder::encode(
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int physicalTrack, int physicalSide, const SectorSet& allSectors)
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{
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/* The format ID Character # 1 and # 2 are in the .d64 image only present
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* in track 18 sector zero which contains the BAM info in byte 162 and 163.
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* it is written in every header of every sector and track. headers are not
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* stored in a d64 disk image so we have to get it from track 18 which
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* contains the BAM.
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*/
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const auto& sectorData = allSectors.get(C64_BAM_TRACK*2, 0, 0); //Read de BAM to get the DISK ID bytes
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if (sectorData)
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{
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ByteReader br(sectorData->data);
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br.seek(162); //goto position of the first Disk ID Byte
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_formatByte1 = br.read_8();
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_formatByte2 = br.read_8();
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}
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else
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_formatByte1 = _formatByte2 = 0;
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int logicalTrack = physicalTrack / 2;
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double clockRateUs = clockRateUsForTrack(logicalTrack) * _config.clock_compensation_factor();
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int bitsPerRevolution = 200000.0 / clockRateUs;
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std::vector<bool> bits(bitsPerRevolution);
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unsigned cursor = 0;
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fillBitmapTo(bits, cursor, _config.post_index_gap_us() / clockRateUs, { true, false });
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lastBit = false;
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unsigned numSectors = sectorsForTrack(logicalTrack);
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unsigned writtenSectors = 0;
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for (int sectorId=0; sectorId<numSectors; sectorId++)
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{
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const auto& sectorData = allSectors.get(physicalTrack, physicalSide, sectorId);
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const auto& sectorData = allSectors.get(C64_BAM_TRACK*2, 0, 0); //Read de BAM to get the DISK ID bytes
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if (sectorData)
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{
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writeSector(bits, cursor, sectorData);
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writtenSectors++;
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ByteReader br(sectorData->data);
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br.seek(162); //goto position of the first Disk ID Byte
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_formatByte1 = br.read_8();
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_formatByte2 = br.read_8();
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}
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else
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_formatByte1 = _formatByte2 = 0;
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int logicalTrack = physicalTrack / 2;
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double clockRateUs = clockRateUsForTrack(logicalTrack) * _config.clock_compensation_factor();
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int bitsPerRevolution = 200000.0 / clockRateUs;
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std::vector<bool> bits(bitsPerRevolution);
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unsigned cursor = 0;
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fillBitmapTo(bits, cursor, _config.post_index_gap_us() / clockRateUs, { true, false });
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lastBit = false;
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unsigned numSectors = sectorsForTrack(logicalTrack);
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unsigned writtenSectors = 0;
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for (int sectorId=0; sectorId<numSectors; sectorId++)
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{
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const auto& sectorData = allSectors.get(physicalTrack, physicalSide, sectorId);
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if (sectorData)
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{
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writeSector(bits, cursor, sectorData);
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writtenSectors++;
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}
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}
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if (writtenSectors == 0)
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return std::unique_ptr<Fluxmap>();
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if (cursor >= bits.size())
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Error() << fmt::format("track data overrun by {} bits", cursor - bits.size());
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fillBitmapTo(bits, cursor, bits.size(), { true, false });
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std::unique_ptr<Fluxmap> fluxmap(new Fluxmap);
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fluxmap->appendBits(bits, clockRateUs*1e3);
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return fluxmap;
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}
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private:
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void writeSector(std::vector<bool>& bits, unsigned& cursor, const Sector* sector) const
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{
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/* Source: http://www.unusedino.de/ec64/technical/formats/g64.html
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* 1. Header sync FF FF FF FF FF (40 'on' bits, not GCR)
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* 2. Header info 52 54 B5 29 4B 7A 5E 95 55 55 (10 GCR bytes)
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* 3. Header gap 55 55 55 55 55 55 55 55 55 (9 bytes, never read)
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* 4. Data sync FF FF FF FF FF (40 'on' bits, not GCR)
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* 5. Data block 55...4A (325 GCR bytes)
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* 6. Inter-sector gap 55 55 55 55...55 55 (4 to 12 bytes, never read)
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* 1. Header sync (SYNC for the next sector)
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*/
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if ((sector->status == Sector::OK) or (sector->status == Sector::BAD_CHECKSUM))
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{
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// There is data to encode to disk.
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if ((sector->data.size() != C64_SECTOR_LENGTH))
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Error() << fmt::format("unsupported sector size {} --- you must pick 256", sector->data.size());
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// 1. Write header Sync (not GCR)
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for (int i=0; i<6; i++)
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write_bits(bits, cursor, C64_HEADER_DATA_SYNC, 1*8); /* sync */
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// 2. Write Header info 10 GCR bytes
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/*
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* The 10 byte header info (#2) is GCR encoded and must be decoded to
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* it's normal 8 bytes to be understood. Once decoded, its breakdown is
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* as follows:
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*
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* Byte $00 - header block ID ($08)
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* 01 - header block checksum 16 (EOR of $02-$05)
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* 02 - Sector
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* 03 - Track
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* 04 - Format ID byte #2
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* 05 - Format ID byte #1
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* 06-07 - $0F ("off" bytes)
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*/
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uint8_t encodedTrack = ((sector->logicalTrack) + 1); // C64 track numbering starts with 1. Fluxengine with 0.
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uint8_t encodedSector = sector->logicalSector;
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// uint8_t formatByte1 = C64_FORMAT_ID_BYTE1;
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// uint8_t formatByte2 = C64_FORMAT_ID_BYTE2;
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uint8_t headerChecksum = (encodedTrack ^ encodedSector ^ _formatByte1 ^ _formatByte2);
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write_bits(bits, cursor, encode_data(C64_HEADER_BLOCK_ID));
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write_bits(bits, cursor, encode_data(headerChecksum));
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write_bits(bits, cursor, encode_data(encodedSector));
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write_bits(bits, cursor, encode_data(encodedTrack));
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write_bits(bits, cursor, encode_data(_formatByte2));
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write_bits(bits, cursor, encode_data(_formatByte1));
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write_bits(bits, cursor, encode_data(C64_PADDING));
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write_bits(bits, cursor, encode_data(C64_PADDING));
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// 3. Write header GAP not GCR
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for (int i=0; i<9; i++)
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write_bits(bits, cursor, C64_HEADER_GAP, 1*8); /* header gap */
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// 4. Write Data sync not GCR
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for (int i=0; i<6; i++)
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write_bits(bits, cursor, C64_HEADER_DATA_SYNC, 1*8); /* sync */
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// 5. Write data block 325 GCR bytes
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/*
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* The 325 byte data block (#5) is GCR encoded and must be decoded to its
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* normal 260 bytes to be understood. The data block is made up of the following:
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*
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* Byte $00 - data block ID ($07)
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* 01-100 - 256 bytes data
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* 101 - data block checksum (EOR of $01-100)
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* 102-103 - $00 ("off" bytes, to make the sector size a multiple of 5)
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*/
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write_bits(bits, cursor, encode_data(C64_DATA_BLOCK_ID));
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uint8_t dataChecksum = xorBytes(sector->data);
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ByteReader br(sector->data);
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int i = 0;
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for (i = 0; i < C64_SECTOR_LENGTH; i++)
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{
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uint8_t val = br.read_8();
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write_bits(bits, cursor, encode_data(val));
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}
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write_bits(bits, cursor, encode_data(dataChecksum));
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write_bits(bits, cursor, encode_data(C64_PADDING));
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write_bits(bits, cursor, encode_data(C64_PADDING));
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//6. Write inter-sector gap 9 - 12 bytes nor gcr
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for (int i=0; i<9; i++)
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write_bits(bits, cursor, C64_INTER_SECTOR_GAP, 1*8); /* sync */
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}
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}
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if (writtenSectors == 0)
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return std::unique_ptr<Fluxmap>();
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private:
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const Commodore64EncoderProto& _config;
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uint8_t _formatByte1;
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uint8_t _formatByte2;
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};
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if (cursor >= bits.size())
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Error() << fmt::format("track data overrun by {} bits", cursor - bits.size());
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fillBitmapTo(bits, cursor, bits.size(), { true, false });
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std::unique_ptr<Fluxmap> fluxmap(new Fluxmap);
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fluxmap->appendBits(bits, clockRateUs*1e3);
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return fluxmap;
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std::unique_ptr<AbstractEncoder> createCommodore64Encoder(const EncoderProto& config)
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{
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return std::unique_ptr<AbstractEncoder>(new Commodore64Encoder(config));
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}
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// vim: sw=4 ts=4 et
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