Add support for DVK MX format and --scale option

include/BitstreamDecoder.h

@@ -10,11 +10,13 @@ void scan_flux_mfm_fm (TrackData &trackdata, DataRate last_datarate);
 void scan_flux_amiga (TrackData &trackdata);
 void scan_flux_gcr (TrackData &trackdata);
 void scan_flux_ace (TrackData &trackdata);
+void scan_flux_mx (TrackData &trackdata);
 
 void scan_bitstream (TrackData &trackdata);
 void scan_bitstream_mfm_fm (TrackData &trackdata);
 void scan_bitstream_amiga (TrackData &trackdata);
 void scan_bitstream_ace (TrackData &trackdata);
 void scan_bitstream_gcr (TrackData &trackdata);
+void scan_bitstream_mx (TrackData &trackdata);
 
 #endif // BITSTREAM_DECODER_H

include/Header.h

@@ -2,7 +2,7 @@
 #define HEADER_H
 
 enum class DataRate : int { Unknown = 0, _250K = 250'000, _300K = 300'000, _500K = 500'000, _1M = 1'000'000 };
-enum class Encoding { Unknown, MFM, FM, Amiga, GCR, Ace };
+enum class Encoding { Unknown, MFM, FM, Amiga, GCR, Ace, MX };
 
 std::string to_string (const DataRate &datarate);
 std::string to_string (const Encoding &encoding);

include/SAMdisk.h

@@ -267,8 +267,8 @@ typedef struct
 	int offsets = -1, absoffsets = 0, nowrite = 0, nodiff = 0, noformat = 0, nodups = 0, rpm = 0, flip = 0;
 	int base = -1, size = -1, gap3 = -1, interleave = -1, skew = -1, fill = -1, fm = -1, head0 = -1, head1 = -1;
 	int maxcopies = 3, fmoverlap = 0, multiformat = 0, cylsfirst = -1;
-	int bdos = 0, atom = 0, hdf = 0, cpm = 0, resize = 0, nocfa = 0, noidentify = 0, ace = 0;
-	int force = 0, nosig = 0, check8k = -1, tty = 0, nodata = 0, noflux = 0, nowobble = 0;
+	int bdos = 0, atom = 0, hdf = 0, cpm = 0, resize = 0, nocfa = 0, noidentify = 0, ace = 0, mx = 0;
+	int force = 0, nosig = 0, check8k = -1, tty = 0, nodata = 0, noflux = 0, nowobble = 0, scale = 100;
 	int time = 0, rate = -1, mt = -1;
 	long sectors = -1;
 	std::string label {}, boot {};

src/BitstreamDecoder.cpp

@@ -38,6 +38,12 @@ void scan_flux (TrackData &trackdata)
 		return;
 	}
 
+	if (opt.mx)
+	{
+		scan_flux_mx(trackdata);
+		return;
+	}
+
 	// Set the encoding scanning order, with the last successful encoding first (and its duplicate removed)
 	std::vector<Encoding> encodings = { last_encoding, Encoding::MFM, Encoding::Amiga/*, Encoding::GCR*/ };
 	encodings.erase(std::next(std::find(encodings.rbegin(), encodings.rend(), last_encoding)).base());
@@ -107,6 +113,12 @@ void scan_bitstream (TrackData &trackdata)
 		return;
 	}
 
+	if (opt.mx)
+	{
+		scan_bitstream_mx(trackdata);
+		return;
+	}
+
 	// Set the encoding scanning order, with the last successful encoding first (and its duplicate removed)
 	std::vector<Encoding> encodings = { last_encoding, Encoding::MFM, Encoding::Amiga/*, Encoding::GCR*/ };
 	encodings.erase(std::next(std::find(encodings.rbegin(), encodings.rend(), last_encoding)).base());
@@ -374,6 +386,106 @@ void scan_flux_ace (TrackData &trackdata)
 }
 
 
+/*
+ * DVK MX format.  DVK was a family of DEC LSI-11 compatible computers
+ * produced by Soviet Union in 1980's, MX.SYS is the RT-11 driver name
+ * for the controller.
+ *
+ * FM encoding. Track format is driver-dependent (except the sync word).
+ * Hardware always reads or writes entire track, hence no sector headers.
+ *
+ * 1. gap1 (8 words)
+ * 2. sync (1 word, 000363 octal, regular FM encoding)
+ * 3. zero-based track number (1 word)
+ * 4. 11 sectors:
+ *   data (128 words)
+ *   checksum (1 word)
+ * 5. extra (1..4 words)
+ * 6. gap4 (or unformatted)
+ *
+ * See also http://torlus.com/floppy/forum/viewtopic.php?f=19&t=1384
+ */
+
+void scan_bitstream_mx (TrackData &trackdata)
+{
+	Track track;
+	Data block;
+	uint64_t dword = 0;
+	uint16_t stored_cksum = 0, cksum = 0;
+
+	auto &bitbuf = trackdata.bitstream();
+	bitbuf.seek(0);
+	bitbuf.encoding = Encoding::FM;
+	track.tracklen = bitbuf.track_bitsize();
+	bool sync = false;
+
+	while (!bitbuf.wrapped())
+	{
+		// Give up if no headers were found in the first revolution
+		if (!track.size() && bitbuf.tell() > track.tracklen)
+			break;
+
+		// ignore sync sequences after first one
+		if (sync)
+			break;
+
+		dword = (dword << 1) | bitbuf.read1();
+		if (opt.debug)
+		util::cout << util::fmt ("  s_b_mx %016lx c:h %d:%d\n", dword, trackdata.cylhead.cyl, trackdata.cylhead.head);
+
+		switch (dword)
+		{
+			case 0x88888888aaaa88aa:	// FM-encoded 0x00f3 (000363 octal)
+				sync = true;
+				if (opt.debug) util::cout << "  s_b_mx found sync at " << bitbuf.tell() << "\n";
+				break;
+
+			default:
+				continue;
+		}
+
+		// skip track number
+		bitbuf.read_byte();
+		bitbuf.read_byte();
+
+		// read sectors
+		for (auto s = 0; s < 11; s++) {
+			Sector sector(DataRate::_250K, Encoding::MX, Header(trackdata.cylhead, s, SizeToCode(256)));
+
+			block.clear();
+			cksum = 0;
+
+			for (auto i = 0; i < 128; i++) {
+				auto msb = bitbuf.read_byte();
+				auto lsb = bitbuf.read_byte();
+				cksum += (lsb | (msb << 8));
+				block.push_back(lsb);
+				block.push_back(msb);
+			}
+
+			stored_cksum  = bitbuf.read_byte() << 8;
+			stored_cksum |= bitbuf.read_byte();
+
+			if (opt.debug) util::cout << util::fmt ("cksum s %d disk:calc %06o:%06o (%04x:%04x)\n",
+				s, stored_cksum, cksum, stored_cksum, cksum);
+
+			sector.add(std::move(block), cksum != stored_cksum, 0);
+			track.add(std::move(sector));
+		}
+	}
+
+	trackdata.add(std::move(track));
+}
+
+void scan_flux_mx (TrackData &trackdata)
+{
+	FluxDecoder decoder(trackdata.flux(), ::bitcell_ns(DataRate::_250K), opt.scale);
+	BitBuffer bitbuf(DataRate::_250K, decoder);
+
+	trackdata.add(std::move(bitbuf));
+}
+
+
 #define MFM_MASK	0x55555555UL
 
 static bool amiga_read_dwords (BitBuffer &bitbuf, uint32_t *pdw, size_t dwords, uint32_t &checksum)

src/Header.cpp

@@ -23,6 +23,7 @@ std::string to_string (const Encoding &encoding)
 		case Encoding::GCR:		return "GCR";			break;
 		case Encoding::Amiga:	return "Amiga";			break;
 		case Encoding::Ace:		return "Ace";			break;
+		case Encoding::MX:		return "MX";			break;
 		case Encoding::Unknown:	break;
 	}
 	return "Unknown";
@@ -37,6 +38,7 @@ std::string short_name (const Encoding &encoding)
 		case Encoding::GCR:		return "gcr";			break;
 		case Encoding::Amiga:	return "ami";			break;
 		case Encoding::Ace:		return "ace";			break;
+		case Encoding::MX:		return "mx";			break;
 		case Encoding::Unknown:	break;
 	}
 	return "unk";

src/SAMdisk.cpp

@@ -83,7 +83,7 @@ extern "C" {
 #include "getopt_long.h"
 }
 
-enum { OPT_RPM = 256, OPT_RATE, OPT_LOG, OPT_VERSION, OPT_HEAD0, OPT_HEAD1, OPT_GAPMASK, OPT_MAXCOPIES, OPT_MAXSPLICE, OPT_CHECK8K, OPT_BYTES, OPT_HDF, OPT_ORDER };
+enum { OPT_RPM = 256, OPT_RATE, OPT_LOG, OPT_VERSION, OPT_HEAD0, OPT_HEAD1, OPT_GAPMASK, OPT_MAXCOPIES, OPT_MAXSPLICE, OPT_CHECK8K, OPT_BYTES, OPT_HDF, OPT_ORDER, OPT_SCALE };
 
 struct option long_options[] =
 {
@@ -151,6 +151,7 @@ struct option long_options[] =
 	{ "byte-swap",		  no_argument, &opt.byteswap, 1 },
 	{ "atom",			  no_argument, &opt.byteswap, 1 },
 	{ "ace",			  no_argument, &opt.ace, 1 },
+	{ "mx",				  no_argument, &opt.mx, 1 },
 	{ "quick",			  no_argument, &opt.quick, 1 },
 	{ "repair",			  no_argument, &opt.repair, 1},
 	{ "fix",			  no_argument, &opt.fix, 1 },
@@ -181,6 +182,7 @@ struct option long_options[] =
 	{ "hdf",		required_argument, nullptr, OPT_HDF },
 	{ "order",		required_argument, nullptr, OPT_ORDER },
 	{ "version",		  no_argument, nullptr, OPT_VERSION },
+	{ "scale",		required_argument, nullptr, OPT_SCALE },
 
 	{ 0, 0, 0, 0 }
 };
@@ -303,6 +305,7 @@ bool ParseCommandLine (int argc_, char *argv_[])
 			case OPT_RPM:	if (!GetInt(optarg, opt.rpm) || (opt.rpm != 300 && opt.rpm != 360)) return BadValue("rpm"); break;
 			case OPT_BYTES: if (!GetInt(optarg, opt.bytes) || !opt.bytes) return BadValue("bytes"); break;
 			case OPT_HDF:	if (!GetInt(optarg, opt.hdf) || (opt.hdf != 10 && opt.hdf != 11)) return BadValue("hdf"); break;
+			case OPT_SCALE: if (!GetInt(optarg, opt.scale)) return BadValue("scale"); break;
 
 			case OPT_VERSION:
 				Version();