Files
fluxengine/arch/aeslanier/decoder.cc
2025-03-17 22:33:54 +01:00

66 lines
2.0 KiB
C++

#include "lib/core/globals.h"
#include "lib/decoders/decoders.h"
#include "arch/aeslanier/aeslanier.h"
#include "lib/core/crc.h"
#include "lib/data/fluxmap.h"
#include "lib/data/fluxmapreader.h"
#include "lib/data/fluxpattern.h"
#include "lib/data/sector.h"
#include "lib/core/bytes.h"
#include "fmt/format.h"
#include <string.h>
static const FluxPattern SECTOR_PATTERN(32, AESLANIER_RECORD_SEPARATOR);
/* This is actually M2FM, rather than MFM, but it our MFM/FM decoder copes fine
* with it. */
class AesLanierDecoder : public Decoder
{
public:
AesLanierDecoder(const DecoderProto& config): Decoder(config) {}
nanoseconds_t advanceToNextRecord() override
{
return seekToPattern(SECTOR_PATTERN);
}
void decodeSectorRecord() override
{
/* Skip ID mark (we know it's a AESLANIER_RECORD_SEPARATOR). */
readRawBits(16);
const auto& rawbits = readRawBits(AESLANIER_RECORD_SIZE * 16);
const auto& bytes =
decodeFmMfm(rawbits).slice(0, AESLANIER_RECORD_SIZE);
const auto& reversed = bytes.reverseBits();
_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<Decoder> createAesLanierDecoder(const DecoderProto& config)
{
return std::unique_ptr<Decoder>(new AesLanierDecoder(config));
}