From c375c948c0fc50d942823abc9bdc0de13cfaa2d7 Mon Sep 17 00:00:00 2001
From: David Given <dg@cowlark.com>
Date: Thu, 20 Aug 2020 22:41:14 +0200
Subject: [PATCH] Add boilerplate for the TI DS990 decoder.

---
 arch/tids990/decoder.cc | 61 +++++++++++++++++++++++++++++++++++++++++
 arch/tids990/tids990.h  | 23 ++++++++++++++++
 mkninja.sh              |  2 ++
 src/fe-readtids990.cc   | 26 ++++++++++++++++++
 src/fluxengine.cc       |  2 ++
 5 files changed, 114 insertions(+)
 create mode 100644 arch/tids990/decoder.cc
 create mode 100644 arch/tids990/tids990.h
 create mode 100644 src/fe-readtids990.cc

diff --git a/arch/tids990/decoder.cc b/arch/tids990/decoder.cc
new file mode 100644
index 00000000..e4492ad7
--- /dev/null
+++ b/arch/tids990/decoder.cc
@@ -0,0 +1,61 @@
+#include "globals.h"
+#include "decoders/decoders.h"
+#include "tids990/tids990.h"
+#include "crc.h"
+#include "fluxmap.h"
+#include "decoders/fluxmapreader.h"
+#include "sector.h"
+#include "record.h"
+#include "track.h"
+#include <string.h>
+
+const int SECTOR_SIZE = 256;
+
+const FluxPattern ID_PATTERN(32, 0xaaaaffaf);
+
+AbstractDecoder::RecordType TiDs990Decoder::advanceToNextRecord()
+{
+      return UNKNOWN_RECORD;
+//    if (_currentSector == -1)
+//    {
+//        /* First sector in the track: look for the sync marker. */
+//        const FluxMatcher* matcher = nullptr;
+//        _sector->clock = _clock = _fmr->seekToPattern(ID_PATTERN, matcher);
+//        readRawBits(32); /* skip the ID mark */
+//        _logicalTrack = decodeFmMfm(readRawBits(32)).slice(0, 32).reader().read_be16();
+//    }
+//    else if (_currentSector == 10)
+//    {
+//        /* That was the last sector on the disk. */
+//        return UNKNOWN_RECORD;
+//    }
+//    else
+//    {
+//        /* Otherwise we assume the clock from the first sector is still valid.
+//         * The decoder framwork will automatically stop when we hit the end of
+//         * the track. */
+//        _sector->clock = _clock;
+//    }
+//
+//    _currentSector++;
+//    return SECTOR_RECORD;
+}
+
+void TiDs990Decoder::decodeSectorRecord()
+{
+//    auto bits = readRawBits((SECTOR_SIZE+2)*16);
+//    auto bytes = decodeFmMfm(bits).slice(0, SECTOR_SIZE+2).swab();
+//
+//    uint16_t gotChecksum = 0;
+//    ByteReader br(bytes);
+//    for (int i=0; i<(SECTOR_SIZE/2); i++)
+//        gotChecksum += br.read_le16();
+//    uint16_t wantChecksum = br.read_le16();
+//
+//    _sector->logicalTrack = _logicalTrack;
+//    _sector->logicalSide = _track->physicalSide;
+//    _sector->logicalSector = _currentSector;
+//    _sector->data = bytes.slice(0, SECTOR_SIZE);
+//    _sector->status = (gotChecksum == wantChecksum) ? Sector::OK : Sector::BAD_CHECKSUM;
+}
+
diff --git a/arch/tids990/tids990.h b/arch/tids990/tids990.h
new file mode 100644
index 00000000..be5f42d1
--- /dev/null
+++ b/arch/tids990/tids990.h
@@ -0,0 +1,23 @@
+#ifndef TIDS990_H
+#define TIDS990_H
+
+#define TIDS990_RECORD_SIZE 0x516 /* bytes */
+#define TIDS990_ID_SIZE 17
+#define TIDS990_PAYLOAD_SIZE 0x500
+
+class Sector;
+class Fluxmap;
+class Track;
+
+class TiDs990Decoder : public AbstractDecoder
+{
+public:
+    virtual ~TiDs990Decoder() {}
+
+    RecordType advanceToNextRecord();
+    void decodeSectorRecord();
+};
+
+#endif
+
+
diff --git a/mkninja.sh b/mkninja.sh
index a40d1588..290ef65e 100644
--- a/mkninja.sh
+++ b/mkninja.sh
@@ -172,6 +172,7 @@ buildlibrary libbackend.a \
     arch/ibm/encoder.cc \
     arch/macintosh/decoder.cc \
     arch/mx/decoder.cc \
+	arch/tids990/decoder.cc \
     arch/victor9k/decoder.cc \
     arch/zilogmcz/decoder.cc \
     lib/bytes.cc \
@@ -223,6 +224,7 @@ buildlibrary libfrontend.a \
     src/fe-readibm.cc \
     src/fe-readmac.cc \
     src/fe-readmx.cc \
+	src/fe-readtids990.cc \
     src/fe-readvictor9k.cc \
     src/fe-readzilogmcz.cc \
     src/fe-rpm.cc \
diff --git a/src/fe-readtids990.cc b/src/fe-readtids990.cc
new file mode 100644
index 00000000..de4a9601
--- /dev/null
+++ b/src/fe-readtids990.cc
@@ -0,0 +1,26 @@
+#include "globals.h"
+#include "flags.h"
+#include "reader.h"
+#include "fluxmap.h"
+#include "decoders/decoders.h"
+#include "sector.h"
+#include "sectorset.h"
+#include "record.h"
+#include "tids990/tids990.h"
+#include "fmt/format.h"
+
+static FlagGroup flags { &readerFlags };
+
+int mainReadTiDs990(int argc, const char* argv[])
+{
+	setReaderDefaultSource(":t=0-79:s=0");
+	setReaderDefaultOutput("dfs.img");
+    setReaderRevolutions(2);
+    flags.parseFlags(argc, argv);
+
+	TiDs990Decoder decoder;
+	readDiskCommand(decoder);
+    return 0;
+}
+
+
diff --git a/src/fluxengine.cc b/src/fluxengine.cc
index 25f6d252..19d490ef 100644
--- a/src/fluxengine.cc
+++ b/src/fluxengine.cc
@@ -22,6 +22,7 @@ extern command_cb mainReadFB100;
 extern command_cb mainReadIBM;
 extern command_cb mainReadMac;
 extern command_cb mainReadMx;
+extern command_cb mainReadTiDs990;
 extern command_cb mainReadVictor9K;
 extern command_cb mainReadZilogMCZ;
 extern command_cb mainRpm;
@@ -77,6 +78,7 @@ static std::vector<Command> readables =
     { "ibm",           mainReadIBM,       "Reads the ubiquitous IBM format disks.", },
     { "mac",           mainReadMac,       "Reads Apple Macintosh disks.", },
     { "mx",            mainReadMx,        "Reads MX disks.", },
+	{ "tids990",       mainReadTiDs990,   "Reads Texas Instruments DS990 disks.", },
     { "victor9k",      mainReadVictor9K,  "Reads Victor 9000 disks.", },
     { "zilogmcz",      mainReadZilogMCZ,  "Reads Zilog MCZ disks.", },
 };