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Convert the AES Lanier decoder.

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This commit is contained in:
David Given
2021-07-11 12:55:05 +02:00
parent f8674230ed
commit 92aa28cac2
3 changed files with 52 additions and 53 deletions
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14
arch/aeslanier/aeslanier.h
View File

@@ -5,20 +5,6 @@
#define AESLANIER_SECTOR_LENGTH 256
#define AESLANIER_RECORD_SIZE (AESLANIER_SECTOR_LENGTH + 5)
class Sector;
class Fluxmap;
class AesLanierDecoderProto;
class AesLanierDecoder : public AbstractDecoder
{
public:
AesLanierDecoder(const AesLanierDecoderProto&) {}
virtual ~AesLanierDecoder() {}
RecordType advanceToNextRecord();
void decodeSectorRecord();
};
extern std::unique_ptr<AbstractDecoder> createAesLanierDecoder(const DecoderProto& config);
#endif

85
arch/aeslanier/decoder.cc
View File

@@ -24,42 +24,57 @@ static Bytes reverse_bits(const Bytes& input)
return output;
}
AbstractDecoder::RecordType AesLanierDecoder::advanceToNextRecord()
class AesLanierDecoder : public AbstractDecoder
{
_sector->clock = _fmr->seekToPattern(SECTOR_PATTERN);
if (_fmr->eof() || !_sector->clock)
return UNKNOWN_RECORD;
return SECTOR_RECORD;
public:
AesLanierDecoder(const DecoderProto& config):
AbstractDecoder(config)
{}
RecordType advanceToNextRecord()
{
_sector->clock = _fmr->seekToPattern(SECTOR_PATTERN);
if (_fmr->eof() || !_sector->clock)
return UNKNOWN_RECORD;
return SECTOR_RECORD;
}
void decodeSectorRecord()
{
/* Skip ID mark. */
readRawBits(16);
const auto& rawbits = readRawBits(AESLANIER_RECORD_SIZE*16);
const auto& bytes = decodeFmMfm(rawbits).slice(0, AESLANIER_RECORD_SIZE);
const auto& reversed = reverse_bits(bytes);
_sector->logicalTrack = reversed[1];
_sector->logicalSide = 0;
_sector->logicalSector = reversed[2];
/* Check header 'checksum' (which seems far too simple to mean much). */
{
uint8_t wanted = reversed[3];
uint8_t got = reversed[1] + reversed[2];
if (wanted != got)
return;
}
/* Check data checksum, which also includes the header and is
* significantly better. */
_sector->data = reversed.slice(1, AESLANIER_SECTOR_LENGTH);
uint16_t wanted = reversed.reader().seek(0x101).read_le16();
uint16_t got = crc16ref(MODBUS_POLY_REF, _sector->data);
_sector->status = (wanted == got) ? Sector::OK : Sector::BAD_CHECKSUM;
}
};
std::unique_ptr<AbstractDecoder> createAesLanierDecoder(const DecoderProto& config)
{
return std::unique_ptr<AbstractDecoder>(new AesLanierDecoder(config));
}
void AesLanierDecoder::decodeSectorRecord()
{
/* Skip ID mark. */
readRawBits(16);
const auto& rawbits = readRawBits(AESLANIER_RECORD_SIZE*16);
const auto& bytes = decodeFmMfm(rawbits).slice(0, AESLANIER_RECORD_SIZE);
const auto& reversed = reverse_bits(bytes);
_sector->logicalTrack = reversed[1];
_sector->logicalSide = 0;
_sector->logicalSector = reversed[2];
/* Check header 'checksum' (which seems far too simple to mean much). */
{
uint8_t wanted = reversed[3];
uint8_t got = reversed[1] + reversed[2];
if (wanted != got)
return;
}
/* Check data checksum, which also includes the header and is
* significantly better. */
_sector->data = reversed.slice(1, AESLANIER_SECTOR_LENGTH);
uint16_t wanted = reversed.reader().seek(0x101).read_le16();
uint16_t got = crc16ref(MODBUS_POLY_REF, _sector->data);
_sector->status = (wanted == got) ? Sector::OK : Sector::BAD_CHECKSUM;
}

6
lib/decoders/decoders.cc
View File

@@ -32,7 +32,8 @@ std::unique_ptr<AbstractDecoder> AbstractDecoder::create(const DecoderProto& con
static const std::map<int,
std::function<std::unique_ptr<AbstractDecoder>(const DecoderProto&)>> decoders =
{
{ DecoderProto::kAmiga, createAmigaDecoder },
{ DecoderProto::kAeslanier, createAesLanierDecoder },
{ DecoderProto::kAmiga, createAmigaDecoder },
};
auto decoder = decoders.find(config.format_case());
@@ -50,9 +51,6 @@ std::unique_ptr<AbstractDecoder> AbstractDecoder::create(const DecoderProto& con
case DecoderProto::kAeslanier:
return std::unique_ptr<AbstractDecoder>(new AesLanierDecoder(config.aeslanier()));
case DecoderProto::kAmiga:
return std::unique_ptr<AbstractDecoder>(new AmigaDecoder(config.amiga()));
case DecoderProto::kApple2:
return std::unique_ptr<AbstractDecoder>(new Apple2Decoder(config.apple2()));