Add swapSides parameter to the Atari ST writer.

arch/ibm/encoder.cc

@@ -102,6 +102,8 @@ static uint8_t decodeUint16(uint16_t raw)
 std::unique_ptr<Fluxmap> IbmEncoder::encode(
 	int physicalTrack, int physicalSide, const SectorSet& allSectors)
 {
+	if (_parameters.swapSides)
+		physicalSide = 1 - physicalSide;
 	double clockRateUs = 1e3 / _parameters.clockRateKhz;
 	if (!_parameters.useFm)
 		clockRateUs /= 2.0;

arch/ibm/ibm.h

@@ -69,6 +69,7 @@ struct IbmParameters
 	int gap2;
 	int gap3;
 	std::string sectorSkew;
+	bool swapSides;
 };
 
 class IbmEncoder : public AbstractEncoder

src/fe-writeatarist.cc

@@ -33,6 +33,11 @@ static StringFlag sectorSkew(
 	"Order to emit sectors.",
 	"");
 
+static BoolFlag swapSides(
+	{ "--ibm-swap-sides" },
+	"Swap sides while writing.",
+	false);
+
 static ActionFlag preset360(
 	{ "--st-preset-360" },
 	"Preset parameters to a 3.5\" 360kB disk (1 side, 80 tracks, 9 sectors).",
@@ -124,6 +129,7 @@ int mainWriteAtariST(int argc, const char* argv[])
 	parameters.gap2 = gap2;
 	parameters.gap3 = gap3;
 	parameters.sectorSkew = sectorSkew;
+	parameters.swapSides = swapSides;
 
 	IbmEncoder encoder(parameters);
 	writeDiskCommand(encoder);

src/fe-writeibm.cc

@@ -74,6 +74,11 @@ static StringFlag sectorSkew(
 	"Order to emit sectors.",
 	"");
 
+static BoolFlag swapSides(
+	{ "--ibm-swap-sides" },
+	"Swap sides while writing. Needed for Commodore 1581, CMD FD-2000, Thomson TO7.",
+	false);
+
 static ActionFlag preset1440(
 	{ "--ibm-preset-1440" },
 	"Preset parameters to a 3.5\" 1440kB disk.",
@@ -129,10 +134,10 @@ int mainWriteIbm(int argc, const char* argv[])
 	parameters.gap2 = gap2;
 	parameters.gap3 = gap3;
 	parameters.sectorSkew = sectorSkew;
+	parameters.swapSides = swapSides;
 
 	IbmEncoder encoder(parameters);
 	writeDiskCommand(encoder);
 
     return 0;
 }
-