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-rw-r--r--src/lib/formats/dmk_dsk.cpp228
1 files changed, 228 insertions, 0 deletions
diff --git a/src/lib/formats/dmk_dsk.cpp b/src/lib/formats/dmk_dsk.cpp
new file mode 100644
index 00000000000..aa37206f736
--- /dev/null
+++ b/src/lib/formats/dmk_dsk.cpp
@@ -0,0 +1,228 @@
+// 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 <assert.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++)
+ {
+ std::vector<UINT8> track_data(track_size);
+ std::vector<UINT32> raw_track_data;
+ int iam_location = -1;
+ int idam_location[64];
+ int dam_location[64];
+
+ // Read track
+ io_generic_read(io, &track_data[0], 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, 16, 0x5224);
+ raw_w(raw_track_data, 16, 0x5224);
+ raw_w(raw_track_data, 16, 0x5224);
+ offset += 3;
+ }
+
+ if (offset == idam_location[idam_index])
+ {
+ raw_w(raw_track_data, 16, 0x4489);
+ raw_w(raw_track_data, 16, 0x4489);
+ raw_w(raw_track_data, 16, 0x4489);
+ idam_index += 1;
+ offset += 3;
+ }
+
+ if (offset == dam_location[dam_index])
+ {
+ raw_w(raw_track_data, 16, 0x4489);
+ raw_w(raw_track_data, 16, 0x4489);
+ raw_w(raw_track_data, 16, 0x4489);
+ dam_index += 1;
+ offset += 3;
+ }
+
+ mfm_w(raw_track_data, 8, track_data[offset]);
+ }
+
+ generate_track_from_levels(track, head, raw_track_data, 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>;