Files
fluxengine/arch/f85/decoder.cc

101 lines
2.6 KiB
C++

#include "globals.h"
#include "fluxmap.h"
#include "decoders/fluxmapreader.h"
#include "protocol.h"
#include "record.h"
#include "decoders/decoders.h"
#include "sector.h"
#include "f85.h"
#include "crc.h"
#include "bytes.h"
#include "fmt/format.h"
#include <string.h>
#include <algorithm>
const FluxPattern SECTOR_RECORD_PATTERN(24, F85_SECTOR_RECORD);
const FluxPattern DATA_RECORD_PATTERN(24, F85_DATA_RECORD);
const FluxMatchers ANY_RECORD_PATTERN({ &SECTOR_RECORD_PATTERN, &DATA_RECORD_PATTERN });
static int decode_data_gcr(uint8_t gcr)
{
switch (gcr)
{
#define GCR_ENTRY(gcr, data) \
case gcr: return data;
#include "data_gcr.h"
#undef GCR_ENTRY
}
return -1;
};
static Bytes decode(const std::vector<bool>& bits)
{
Bytes output;
ByteWriter bw(output);
BitWriter bitw(bw);
auto ii = bits.begin();
while (ii != bits.end())
{
uint8_t inputfifo = 0;
for (size_t i=0; i<5; i++)
{
if (ii == bits.end())
break;
inputfifo = (inputfifo<<1) | *ii++;
}
bitw.push(decode_data_gcr(inputfifo), 4);
}
bitw.flush();
return output;
}
AbstractDecoder::RecordType DurangoF85Decoder::advanceToNextRecord()
{
const FluxMatcher* matcher = nullptr;
_sector->clock = _fmr->seekToPattern(ANY_RECORD_PATTERN, matcher);
if (matcher == &SECTOR_RECORD_PATTERN)
return RecordType::SECTOR_RECORD;
if (matcher == &DATA_RECORD_PATTERN)
return RecordType::DATA_RECORD;
return RecordType::UNKNOWN_RECORD;
}
void DurangoF85Decoder::decodeSectorRecord()
{
/* Skip sync bits and ID byte. */
readRawBits(24);
/* Read header. */
const auto& bytes = decode(readRawBits(6*10));
_sector->logicalSector = bytes[2];
_sector->logicalSide = 0;
_sector->logicalTrack = bytes[0];
uint16_t wantChecksum = bytes.reader().seek(4).read_be16();
uint16_t gotChecksum = crc16(CCITT_POLY, 0xef21, bytes.slice(0, 4));
if (wantChecksum == gotChecksum)
_sector->status = Sector::DATA_MISSING; /* unintuitive but correct */
}
void DurangoF85Decoder::decodeDataRecord()
{
/* Skip sync bits ID byte. */
readRawBits(24);
const auto& bytes = decode(readRawBits((F85_SECTOR_LENGTH+3)*10))
.slice(0, F85_SECTOR_LENGTH+3);
ByteReader br(bytes);
_sector->data = br.read(F85_SECTOR_LENGTH);
uint16_t wantChecksum = br.read_be16();
uint16_t gotChecksum = crc16(CCITT_POLY, 0xbf84, _sector->data);
_sector->status = (wantChecksum == gotChecksum) ? Sector::OK : Sector::BAD_CHECKSUM;
}