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Get the Tartu checksums working, and hook up the CP/M filesystem code.

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This commit is contained in:
David Given
2024-04-21 00:17:11 +02:00
parent 15d34aff15
commit 2732d9aec8
2 changed files with 66 additions and 2 deletions
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50
arch/tartu/decoder.cc
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@@ -7,6 +7,17 @@
#include "lib/sector.h"
#include <string.h>
constexpr uint64_t HEADER_BITS = 0xaaaaaaaa44895554LL;
constexpr uint64_t DATA_BITS = 0xaaaaaaaa44895545LL;
static const FluxPattern HEADER_PATTERN(64, HEADER_BITS);
static const FluxPattern DATA_PATTERN(64, DATA_BITS);
const FluxMatchers ANY_RECORD_PATTERN {
&HEADER_PATTERN,
&DATA_PATTERN
};
class TartuDecoder : public Decoder
{
public:
@@ -16,13 +27,50 @@ public:
{
}
void beginTrack() override
{
}
nanoseconds_t advanceToNextRecord() override
{
return 0;
return seekToPattern(ANY_RECORD_PATTERN);
}
void decodeSectorRecord() override
{
if (readRaw64() != HEADER_BITS)
return;
auto bits = readRawBits(16 * 8);
auto bytes = decodeFmMfm(bits).slice(0, 8);
ByteReader br(bytes);
uint8_t track = br.read_8();
_sector->logicalTrack = track >> 1;
_sector->logicalSide = track & 1;
br.skip(1); /* seems always to be 1 */
_sector->logicalSector = br.read_8();
uint8_t wantChecksum = br.read_8();
uint8_t gotChecksum = ~sumBytes(bytes.slice(0, 3));
if (wantChecksum == gotChecksum)
_sector->status = Sector::DATA_MISSING;
_sector->status = Sector::DATA_MISSING;
}
void decodeDataRecord() override
{
if (readRaw64() != DATA_BITS)
return;
const auto& bits = readRawBits(129 * 16);
const auto& bytes = decodeFmMfm(bits).slice(0, 129);
_sector->data = bytes.slice(0, 128);
uint8_t wantChecksum = bytes.reader().seek(128).read_8();
uint8_t gotChecksum = ~sumBytes(_sector->data);
_sector->status = (wantChecksum == gotChecksum) ? Sector::OK : Sector::BAD_CHECKSUM;
}
private: