Add some helper methods to make decoders easier. Port IBM to the new new

architecture.
2025-10-24 11:11:02 -07:00 · 2019-04-30 20:45:16 +02:00
parent 4cc680057e
commit 184e7766f0
5 changed files with 137 additions and 138 deletions
--- a/lib/brother/decoder.cc
+++ b/lib/brother/decoder.cc
@@ -66,8 +66,8 @@ AbstractSimplifiedDecoder::RecordType BrotherDecoder::advanceToNextRecord()

 void BrotherDecoder::decodeSectorRecord()
 {
-	_fmr->readRawBits(32, _sector->clock);
-	const auto& rawbits = _fmr->readRawBits(32, _sector->clock);
+	readRawBits(32);
+	const auto& rawbits = readRawBits(32);
 	const auto& bytes = toBytes(rawbits).slice(0, 4);

 	ByteReader br(bytes);
@@ -86,9 +86,9 @@ void BrotherDecoder::decodeSectorRecord()

 void BrotherDecoder::decodeDataRecord()
 {
-	_fmr->readRawBits(32, _sector->clock);
+	readRawBits(32);

-	const auto& rawbits = _fmr->readRawBits(BROTHER_DATA_RECORD_ENCODED_SIZE*8, _sector->clock);
+	const auto& rawbits = readRawBits(BROTHER_DATA_RECORD_ENCODED_SIZE*8);
 	const auto& rawbytes = toBytes(rawbits).slice(0, BROTHER_DATA_RECORD_ENCODED_SIZE);

 	Bytes bytes;
--- a/lib/decoders/decoders.h
+++ b/lib/decoders/decoders.h
@@ -4,6 +4,7 @@
 #include "bytes.h"
 #include "sector.h"
 #include "record.h"
+#include "fluxmapreader.h"

 class Sector;
 class Fluxmap;
@@ -48,6 +49,15 @@ public:
    void decodeToSectors(Track& track) override;
    void pushRecord(const Fluxmap::Position& start, const Fluxmap::Position& end);

+    std::vector<bool> readRawBits(unsigned count)
+    { return _fmr->readRawBits(count, _sector->clock); }
+
+    Fluxmap::Position tell()
+    { return _fmr->tell(); } 
+
+    void seek(const Fluxmap::Position& pos)
+    { return _fmr->seek(pos); } 
+
 protected:
    virtual RecordType advanceToNextRecord() = 0;
    virtual void decodeSectorRecord() = 0;
--- a/lib/ibm/decoder.cc
+++ b/lib/ibm/decoder.cc
@@ -76,7 +76,7 @@ const FluxPattern FM_TRS80DAM2_PATTERN(16, 0xf56c);
 */
 const FluxPattern MFM_PATTERN(16, 0x4489);

-const FluxMatchers SEPARATOR_PATTERNS(
+const FluxMatchers ANY_RECORD_PATTERN(
    {
        &MFM_PATTERN,
        &FM_IDAM_PATTERN,
@@ -87,77 +87,67 @@ const FluxMatchers SEPARATOR_PATTERNS(
    }
 );

-nanoseconds_t IbmDecoder::findSector(FluxmapReader& fmr, Track& track)
+AbstractSimplifiedDecoder::RecordType IbmDecoder::advanceToNextRecord()
 {
-    for (;;)
+	const FluxMatcher* matcher = nullptr;
+	_sector->clock = _fmr->seekToPattern(ANY_RECORD_PATTERN, matcher);
+
+    /* If this is the MFM prefix byte, the the decoder is going to expect three
+     * extra bytes on the front of the header. */
+    _currentHeaderLength = (matcher == &MFM_PATTERN) ? 3 : 0;
+
+    Fluxmap::Position here = tell();
+    if (_currentHeaderLength > 0)
+        readRawBits(_currentHeaderLength*16);
+    auto idbits = readRawBits(16);
+    uint8_t id = decodeFmMfm(idbits).slice(0, 1)[0];
+    seek(here);
+    
+    switch (id)
    {
-        nanoseconds_t clock = fmr.seekToPattern(SEPARATOR_PATTERNS);
-        if (fmr.eof() || !clock)
-            return 0;
+        case IBM_IDAM:
+            return RecordType::SECTOR_RECORD;

-        auto here = fmr.tell();
-        auto idbits = fmr.readRawBits(16, clock);
-        uint8_t id = decodeFmMfm(idbits).slice(0, 1)[0];
-        fmr.seek(here);
-        /* If this is the MFM prefix byte, the the decoder is going to expect three
-         * extra bytes on the front of the header. */
-        _currentHeaderLength = (id == IBM_MFM_SYNC) ? 3 : 0;
-
-        switch (id)
-        {
-            case IBM_MFM_SYNC:
-            case IBM_IDAM:
-            case IBM_DAM1:
-            case IBM_DAM2:
-            case IBM_TRS80DAM1:
-            case IBM_TRS80DAM2:
-                return clock;
-        }
-
-        fmr.readRawBit(clock);
+        case IBM_DAM1:
+        case IBM_DAM2:
+        case IBM_TRS80DAM1:
+        case IBM_TRS80DAM2:
+            return RecordType::DATA_RECORD;
    }
+    return RecordType::UNKNOWN_RECORD;
 }

-nanoseconds_t IbmDecoder::findData(FluxmapReader& fmr, Track& track)
-{
-    return findSector(fmr, track);
-}
-
-void IbmDecoder::decodeHeader(FluxmapReader& fmr, Track& track, Sector& sector)
+void IbmDecoder::decodeSectorRecord()
 {
    unsigned recordSize = _currentHeaderLength + IBM_IDAM_LEN;
-    auto bits = fmr.readRawBits(recordSize*16, sector.clock);
+    auto bits = readRawBits(recordSize*16);
    auto bytes = decodeFmMfm(bits).slice(0, recordSize);

    ByteReader br(bytes);
    br.seek(_currentHeaderLength);
-    uint8_t id = br.read_8();
-    if (id != IBM_IDAM)
-        return;
-    sector.logicalTrack = br.read_8();
-    sector.logicalSide = br.read_8();
-    sector.logicalSector = br.read_8() - _sectorBase;
+    br.read_8(); /* skip ID byte */
+    _sector->logicalTrack = br.read_8();
+    _sector->logicalSide = br.read_8();
+    _sector->logicalSector = br.read_8() - _sectorBase;
    _currentSectorSize = 1 << (br.read_8() + 7);
    uint16_t wantCrc = br.read_be16();
    uint16_t gotCrc = crc16(CCITT_POLY, bytes.slice(0, _currentHeaderLength + 5));
    if (wantCrc == gotCrc)
-        sector.status = Sector::DATA_MISSING; /* correct but unintuitive */
+        _sector->status = Sector::DATA_MISSING; /* correct but unintuitive */
 }

-void IbmDecoder::decodeData(FluxmapReader& fmr, Track& track, Sector& sector)
+void IbmDecoder::decodeDataRecord()
 {
    unsigned recordLength = _currentHeaderLength + _currentSectorSize + 3;
-    auto bits = fmr.readRawBits(recordLength*16, sector.clock);
+    auto bits = readRawBits(recordLength*16);
    auto bytes = decodeFmMfm(bits).slice(0, recordLength);

    ByteReader br(bytes);
    br.seek(_currentHeaderLength);
-    uint8_t id = br.read_8();
-    if ((id != IBM_DAM1) && (id != IBM_DAM2) && (id != IBM_TRS80DAM1) && (id != IBM_TRS80DAM2))
-        return;
+    br.read_8(); /* skip ID byte */

-    sector.data = br.read(_currentSectorSize);
+    _sector->data = br.read(_currentSectorSize);
    uint16_t wantCrc = br.read_be16();
    uint16_t gotCrc = crc16(CCITT_POLY, bytes.slice(0, recordLength-2));
-    sector.status = (wantCrc == gotCrc) ? Sector::OK : Sector::BAD_CHECKSUM;
+    _sector->status = (wantCrc == gotCrc) ? Sector::OK : Sector::BAD_CHECKSUM;
 }
--- a/lib/ibm/ibm.h
+++ b/lib/ibm/ibm.h
@@ -28,17 +28,16 @@ struct IbmIdam
    uint8_t crc[2];
 };

-class IbmDecoder : public AbstractSplitDecoder
+class IbmDecoder : public AbstractSimplifiedDecoder
 {
 public:
    IbmDecoder(unsigned sectorBase):
        _sectorBase(sectorBase)
    {}

-    nanoseconds_t findSector(FluxmapReader& fmr, Track& track) override;
-    nanoseconds_t findData(FluxmapReader& fmr, Track& track) override;
-    void decodeHeader(FluxmapReader& fmr, Track& track, Sector& sector) override;
-    void decodeData(FluxmapReader& fmr, Track& track, Sector& sector) override;
+    RecordType advanceToNextRecord();
+    void decodeSectorRecord();
+    void decodeDataRecord();

 private:
    unsigned _sectorBase;
--- a/meson.build
+++ b/meson.build
@@ -124,32 +124,32 @@ encoderlib = declare_dependency(
        )
 )

-aeslanierdecoderlib = declare_dependency(
-   link_with:
-       shared_library('aeslanierdecoderlib',
-       [ 'lib/aeslanier/decoder.cc', ],
-       dependencies: [fmtlib, felib, decoderlib]),
-   include_directories:
-       include_directories('lib/aeslanier')
-)
+# aeslanierdecoderlib = declare_dependency(
+#    link_with:
+#        shared_library('aeslanierdecoderlib',
+#        [ 'lib/aeslanier/decoder.cc', ],
+#        dependencies: [fmtlib, felib, decoderlib]),
+#    include_directories:
+#        include_directories('lib/aeslanier')
+# )

-amigadecoderlib = declare_dependency(
-   link_with:
-       shared_library('amigadecoderlib',
-       [ 'lib/amiga/decoder.cc', ],
-       dependencies: [fmtlib, felib, decoderlib]),
-   include_directories:
-       include_directories('lib/amiga')
-)
+# amigadecoderlib = declare_dependency(
+#    link_with:
+#        shared_library('amigadecoderlib',
+#        [ 'lib/amiga/decoder.cc', ],
+#        dependencies: [fmtlib, felib, decoderlib]),
+#    include_directories:
+#        include_directories('lib/amiga')
+# )

-apple2decoderlib = declare_dependency(
-   link_with:
-       shared_library('apple2decoderlib',
-       [ 'lib/apple2/decoder.cc', ],
-       dependencies: [fmtlib, felib, decoderlib]),
-   include_directories:
-       include_directories('lib/apple2')
-)
+# apple2decoderlib = declare_dependency(
+#    link_with:
+#        shared_library('apple2decoderlib',
+#        [ 'lib/apple2/decoder.cc', ],
+#        dependencies: [fmtlib, felib, decoderlib]),
+#    include_directories:
+#        include_directories('lib/apple2')
+# )

 brotherdecoderlib = declare_dependency(
   link_with:
@@ -169,32 +169,32 @@ brotherdecoderlib = declare_dependency(
 #        include_directories('lib/brother')
 #)

-c64decoderlib = declare_dependency(
-   link_with:
-       shared_library('c64decoderlib',
-       [ 'lib/c64/decoder.cc', ],
-       dependencies: [fmtlib, felib, decoderlib]),
-   include_directories:
-       include_directories('lib/c64')
-)
+# c64decoderlib = declare_dependency(
+#    link_with:
+#        shared_library('c64decoderlib',
+#        [ 'lib/c64/decoder.cc', ],
+#        dependencies: [fmtlib, felib, decoderlib]),
+#    include_directories:
+#        include_directories('lib/c64')
+# )

-f85decoderlib = declare_dependency(
-    link_with:
-        shared_library('f85decoderlib',
-        [ 'lib/f85/decoder.cc', ],
-        dependencies: [fmtlib, felib, decoderlib]),
-    include_directories:
-        include_directories('lib/f85')
-)
+# f85decoderlib = declare_dependency(
+#     link_with:
+#         shared_library('f85decoderlib',
+#         [ 'lib/f85/decoder.cc', ],
+#         dependencies: [fmtlib, felib, decoderlib]),
+#     include_directories:
+#         include_directories('lib/f85')
+# )

-fb100decoderlib = declare_dependency(
-    link_with:
-        shared_library('fb100decoderlib',
-        [ 'lib/fb100/decoder.cc', ],
-        dependencies: [fmtlib, felib, decoderlib]),
-    include_directories:
-        include_directories('lib/fb100')
-)
+# fb100decoderlib = declare_dependency(
+#     link_with:
+#         shared_library('fb100decoderlib',
+#         [ 'lib/fb100/decoder.cc', ],
+#         dependencies: [fmtlib, felib, decoderlib]),
+#     include_directories:
+#         include_directories('lib/fb100')
+# )

 ibmdecoderlib = declare_dependency(
    link_with:
@@ -205,49 +205,49 @@ ibmdecoderlib = declare_dependency(
        include_directories('lib/ibm')
 )

-macdecoderlib = declare_dependency(
-    link_with:
-        shared_library('macdecoderlib',
-        [ 'lib/macintosh/decoder.cc', ],
-        dependencies: [fmtlib, felib, decoderlib]),
-    include_directories:
-        include_directories('lib/macintosh')
-)
+# macdecoderlib = declare_dependency(
+#     link_with:
+#         shared_library('macdecoderlib',
+#         [ 'lib/macintosh/decoder.cc', ],
+#         dependencies: [fmtlib, felib, decoderlib]),
+#     include_directories:
+#         include_directories('lib/macintosh')
+# )

-zilogmczdecoderlib = declare_dependency(
-    link_with:
-        shared_library('zilogmczdecoderlib',
-        [ 'lib/zilogmcz/decoder.cc', ],
-        dependencies: [fmtlib, felib, decoderlib]),
-    include_directories:
-        include_directories('lib/zilogmcz')
-)
+# zilogmczdecoderlib = declare_dependency(
+#     link_with:
+#         shared_library('zilogmczdecoderlib',
+#         [ 'lib/zilogmcz/decoder.cc', ],
+#         dependencies: [fmtlib, felib, decoderlib]),
+#     include_directories:
+#         include_directories('lib/zilogmcz')
+# )

-victor9kdecoderlib = declare_dependency(
-    link_with:
-        shared_library('victor9kdecoderlib',
-        [ 'lib/victor9k/decoder.cc', ],
-        dependencies: [fmtlib, felib, decoderlib]),
-    include_directories:
-        include_directories('lib/victor9k')
-)
+# victor9kdecoderlib = declare_dependency(
+#     link_with:
+#         shared_library('victor9kdecoderlib',
+#         [ 'lib/victor9k/decoder.cc', ],
+#         dependencies: [fmtlib, felib, decoderlib]),
+#     include_directories:
+#         include_directories('lib/victor9k')
+# )

 executable('fe-erase',             ['src/fe-erase.cc'],             dependencies: [felib, writerlib])
 executable('fe-inspect',           ['src/fe-inspect.cc'],           dependencies: [fmtlib, felib, decoderlib, readerlib])
 executable('fe-readadfs',          ['src/fe-readadfs.cc'],          dependencies: [fmtlib, felib, decoderlib, readerlib, ibmdecoderlib])
-executable('fe-readaeslanier',     ['src/fe-readaeslanier.cc'],     dependencies: [fmtlib, felib, decoderlib, readerlib, aeslanierdecoderlib])
-executable('fe-readamiga',         ['src/fe-readamiga.cc'],         dependencies: [fmtlib, felib, decoderlib, readerlib, amigadecoderlib])
-executable('fe-readampro',         ['src/fe-readampro.cc'],         dependencies: [fmtlib, felib, decoderlib, readerlib, ibmdecoderlib])
-executable('fe-readapple2',        ['src/fe-readapple2.cc'],        dependencies: [fmtlib, felib, decoderlib, readerlib, apple2decoderlib])
+# executable('fe-readaeslanier',     ['src/fe-readaeslanier.cc'],     dependencies: [fmtlib, felib, decoderlib, readerlib, aeslanierdecoderlib])
+# executable('fe-readamiga',         ['src/fe-readamiga.cc'],         dependencies: [fmtlib, felib, decoderlib, readerlib, amigadecoderlib])
+# executable('fe-readampro',         ['src/fe-readampro.cc'],         dependencies: [fmtlib, felib, decoderlib, readerlib, ibmdecoderlib])
+# executable('fe-readapple2',        ['src/fe-readapple2.cc'],        dependencies: [fmtlib, felib, decoderlib, readerlib, apple2decoderlib])
 executable('fe-readbrother',       ['src/fe-readbrother.cc'],       dependencies: [fmtlib, felib, decoderlib, readerlib, brotherdecoderlib])
-executable('fe-readc64',           ['src/fe-readc64.cc'],           dependencies: [fmtlib, felib, decoderlib, readerlib, c64decoderlib])
+# executable('fe-readc64',           ['src/fe-readc64.cc'],           dependencies: [fmtlib, felib, decoderlib, readerlib, c64decoderlib])
 executable('fe-readdfs',           ['src/fe-readdfs.cc'],           dependencies: [fmtlib, felib, decoderlib, readerlib, ibmdecoderlib])
-executable('fe-readf85',           ['src/fe-readf85.cc'],           dependencies: [fmtlib, felib, decoderlib, readerlib, f85decoderlib])
-executable('fe-readfb100',         ['src/fe-readfb100.cc'],         dependencies: [fmtlib, felib, decoderlib, readerlib, fb100decoderlib])
+# executable('fe-readf85',           ['src/fe-readf85.cc'],           dependencies: [fmtlib, felib, decoderlib, readerlib, f85decoderlib])
+# executable('fe-readfb100',         ['src/fe-readfb100.cc'],         dependencies: [fmtlib, felib, decoderlib, readerlib, fb100decoderlib])
 executable('fe-readibm',           ['src/fe-readibm.cc'],           dependencies: [fmtlib, felib, decoderlib, readerlib, ibmdecoderlib])
-executable('fe-readmac',           ['src/fe-readmac.cc'],           dependencies: [fmtlib, felib, decoderlib, readerlib, macdecoderlib])
-executable('fe-readzilogmcz',      ['src/fe-readzilogmcz.cc'],      dependencies: [fmtlib, felib, decoderlib, readerlib, zilogmczdecoderlib])
-executable('fe-readvictor9k',      ['src/fe-readvictor9k.cc'],      dependencies: [fmtlib, felib, decoderlib, readerlib, victor9kdecoderlib])
+# executable('fe-readmac',           ['src/fe-readmac.cc'],           dependencies: [fmtlib, felib, decoderlib, readerlib, macdecoderlib])
+# executable('fe-readzilogmcz',      ['src/fe-readzilogmcz.cc'],      dependencies: [fmtlib, felib, decoderlib, readerlib, zilogmczdecoderlib])
+# executable('fe-readvictor9k',      ['src/fe-readvictor9k.cc'],      dependencies: [fmtlib, felib, decoderlib, readerlib, victor9kdecoderlib])
 executable('fe-rpm',               ['src/fe-rpm.cc'],               dependencies: [fmtlib, felib])
 executable('fe-seek',              ['src/fe-seek.cc'],              dependencies: [fmtlib, felib])
 executable('fe-testbulktransport', ['src/fe-testbulktransport.cc'], dependencies: [fmtlib, felib])