(MESS) msx.c: Added support for DMK floppy images. [Wilbert Pol]

.gitattributes

@@ -3798,6 +3798,8 @@ src/lib/formats/dfi_dsk.c svneol=native#text/plain
 src/lib/formats/dfi_dsk.h svneol=native#text/plain
 src/lib/formats/dim_dsk.c svneol=native#text/plain
 src/lib/formats/dim_dsk.h svneol=native#text/plain
+src/lib/formats/dmk_dsk.c svneol=native#text/plain
+src/lib/formats/dmk_dsk.h svneol=native#text/plain
 src/lib/formats/dmv_dsk.c svneol=native#text/plain
 src/lib/formats/dmv_dsk.h svneol=native#text/plain
 src/lib/formats/dsk_dsk.c svneol=native#text/plain

src/lib/formats/dmk_dsk.c

@@ -0,0 +1,229 @@
+// license:BSD-3-Clause
+// copyright-holders:Wilbert Pol
+/*********************************************************************
+
+    formats/dmk_dsk.h
+
+    DMK disk images
+
+TODO:
+- Add write/format support.
+- Add single density support.
+- Check support on other drivers besides msx.
+
+*********************************************************************/
+
+#include "emu.h"
+#include "dmk_dsk.h"
+
+
+dmk_format::dmk_format()
+{
+}
+
+
+const char *dmk_format::name() const
+{
+	return "dmk";
+}
+
+
+const char *dmk_format::description() const
+{
+	return "DMK disk image";
+}
+
+
+const char *dmk_format::extensions() const
+{
+	return "dmk";
+}
+
+
+int dmk_format::identify(io_generic *io, UINT32 form_factor)
+{
+	const int header_size = 16;
+	UINT8 header[header_size];
+
+	UINT64 size = io_generic_size(io);
+
+	io_generic_read(io, header, 0, header_size);
+
+	int tracks = header[1];
+	int track_size = ( header[3] << 8 ) | header[2];
+	int heads = (header[4] & 0x10) ? 1 : 2;
+
+	// The first header byte must be 00 or FF
+	if (header[0] != 0x00 && header[0] != 0xff)
+	{
+		return 0;
+	}
+
+	// Bytes C-F must be zero
+	if (header[0x0c] != 0 || header[0xd] != 0 || header[0xe] != 0 || header[0xf] != 0)
+	{
+		return 0;
+	}
+
+	// Check track size within limits
+	if (track_size < 0x80 || track_size > 0x3FFF )
+	{
+		return 0;
+	}
+
+	if (size == header_size + heads * tracks * track_size)
+	{
+		return 70;
+	}
+
+	return 0;
+}
+
+
+bool dmk_format::load(io_generic *io, UINT32 form_factor, floppy_image *image)
+{
+	const int header_size = 16;
+	UINT8 header[header_size];
+
+	io_generic_read(io, header, 0, header_size);
+
+	const int tracks = header[1];
+	const int track_size = ( header[3] << 8 ) | header[2];
+	const int heads = (header[4] & 0x10) ? 1 : 2;
+	const bool is_sd = (header[4] & 0x40) ? true : false;
+	const int raw_track_size = 2 * 8 * ( track_size - 0x80 );
+
+	if (is_sd)
+	{
+		if (heads == 2)
+		{
+			image->set_variant(floppy_image::DSSD);
+		}
+		else
+		{
+			image->set_variant(floppy_image::SSSD);
+		}
+	}
+	else
+	{
+		if (heads == 2)
+		{
+			image->set_variant(floppy_image::DSDD);
+		}
+		else
+		{
+			image->set_variant(floppy_image::SSDD);
+		}
+	}
+
+	for (int track = 0; track < tracks; track++)
+	{
+		for (int head = 0; head < heads; head++)
+		{
+			dynamic_array<UINT8> track_data(track_size);
+			dynamic_array<UINT32> raw_track_data(raw_track_size);
+			int iam_location = -1;
+			int idam_location[64];
+			int dam_location[64];
+			int tpos = 0;
+
+			// Read track
+			io_generic_read(io, track_data, header_size + ( heads * track + head ) * track_size, track_size);
+
+			for (int i = 0; i < 64; i++)
+			{
+				idam_location[i] = -1;
+				dam_location[i] = -1;
+			}
+
+			// Find IDAM locations
+			UINT16 track_header_offset = 0;
+			UINT16 track_offset = ( ( track_data[track_header_offset + 1] << 8 ) | track_data[track_header_offset] ) & 0x3fff;
+			track_header_offset += 2;
+
+			while ( track_offset != 0 && track_offset >= 0x83 && track_offset < track_size && track_header_offset < 0x80 )
+			{
+				// Assume 3 bytes before IDAM pointers are the start of IDAM indicators
+				idam_location[(track_header_offset/2) - 1] = track_offset - 3;
+
+				// Scan for DAM location
+				for (int i = track_offset + 53; i > track_offset + 10; i--)
+				{
+					if ((track_data[i] == 0xfb || track_data[i] == 0xf8) && track_data[i-1] == 0xa1 && track_data[i-2] == 0xa1)
+					{
+						dam_location[(track_header_offset/2) - 1] = i - 3;
+						break;
+					}
+				}
+
+				track_offset = ( ( track_data[track_header_offset + 1] << 8 ) | track_data[track_header_offset] ) & 0x3fff;
+				track_header_offset += 2;
+			};
+
+			// Find IAM location
+			for(int i = idam_location[0] - 1; i >= 3; i--)
+			{
+				// It's usually 3 bytes but several dumped tracks seem to contain only 2 bytes
+				if (track_data[i] == 0xfc && track_data[i-1] == 0xc2 && track_data[i-2] == 0xc2)
+				{
+					iam_location = i - 3;
+					break;
+				}
+			}
+
+			int idam_index = 0;
+			int dam_index = 0;
+			for (int offset = 0x80; offset < track_size; offset++)
+			{
+				if (offset == iam_location)
+				{
+					// Write IAM
+					raw_w(raw_track_data, tpos, 16, 0x5224);
+					raw_w(raw_track_data, tpos, 16, 0x5224);
+					raw_w(raw_track_data, tpos, 16, 0x5224);
+					offset += 3;
+				}
+
+				if (offset == idam_location[idam_index])
+				{
+					raw_w(raw_track_data, tpos, 16, 0x4489);
+					raw_w(raw_track_data, tpos, 16, 0x4489);
+					raw_w(raw_track_data, tpos, 16, 0x4489);
+					idam_index += 1;
+					offset += 3;
+				}
+
+				if (offset == dam_location[dam_index])
+				{
+					raw_w(raw_track_data, tpos, 16, 0x4489);
+					raw_w(raw_track_data, tpos, 16, 0x4489);
+					raw_w(raw_track_data, tpos, 16, 0x4489);
+					dam_index += 1;
+					offset += 3;
+				}
+
+				mfm_w(raw_track_data, tpos, 8, track_data[offset]);
+			}
+
+			generate_track_from_levels(track, head, raw_track_data, raw_track_size, 0, image);
+		}
+	}
+
+	return true;
+}
+
+
+bool dmk_format::save(io_generic *io, floppy_image *image)
+{
+	return false;
+}
+
+
+bool dmk_format::supports_save() const
+{
+	return false;
+}
+
+
+const floppy_format_type FLOPPY_DMK_FORMAT = &floppy_image_format_creator<dmk_format>;
+

src/lib/formats/dmk_dsk.h

@@ -0,0 +1,34 @@
+/*********************************************************************
+
+    formats/dmk_dsk.h
+
+    DMK disk images
+
+*********************************************************************/
+
+#ifndef DMK_DSK_H
+#define DMK_DSK_H
+
+#include "flopimg.h"
+
+/**************************************************************************/
+
+class dmk_format : public floppy_image_format_t
+{
+public:
+	dmk_format();
+
+	virtual int identify(io_generic *io, UINT32 form_factor);
+	virtual bool load(io_generic *io, UINT32 form_factor, floppy_image *image);
+	virtual bool save(io_generic *io, floppy_image *image);
+
+	virtual const char *name() const;
+	virtual const char *description() const;
+	virtual const char *extensions() const;
+	virtual bool supports_save() const;
+};
+
+extern const floppy_format_type FLOPPY_DMK_FORMAT;
+
+#endif /* DMK_DSK_H */
+

src/mess/drivers/msx.c

@@ -521,6 +521,7 @@ PCB Layouts missing
 #include "includes/msx.h"
 #include "bus/centronics/covox.h"
 #include "formats/dsk_dsk.h"
+#include "formats/dmk_dsk.h"
 #include "machine/msx_matsushita.h"
 #include "machine/msx_s1985.h"
 #include "machine/msx_systemflags.h"
@@ -1258,7 +1259,8 @@ static MACHINE_CONFIG_FRAGMENT( msx2_floplist )
 MACHINE_CONFIG_END
 
 FLOPPY_FORMATS_MEMBER( msx_state::floppy_formats )
-	FLOPPY_MSX_FORMAT
+	FLOPPY_MSX_FORMAT,
+	FLOPPY_DMK_FORMAT
 FLOPPY_FORMATS_END
 
 static SLOT_INTERFACE_START( msx_floppies )