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-rw-r--r--src/lib/formats/jvc_dsk.cpp174
1 files changed, 174 insertions, 0 deletions
diff --git a/src/lib/formats/jvc_dsk.cpp b/src/lib/formats/jvc_dsk.cpp
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index 00000000000..30ec8287f22
--- /dev/null
+++ b/src/lib/formats/jvc_dsk.cpp
@@ -0,0 +1,174 @@
+// license:GPL-2.0+
+// copyright-holders:Dirk Best
+/***************************************************************************
+
+ JVC
+
+ Disk image format
+
+ Named after its creator, Jeff Vavasour
+
+ TODO:
+ - Support writing unusal formats?
+
+***************************************************************************/
+
+#include "emu.h"
+#include "jvc_dsk.h"
+
+jvc_format::jvc_format()
+{
+}
+
+const char *jvc_format::name() const
+{
+ return "jvc";
+}
+
+const char *jvc_format::description() const
+{
+ return "JVC disk image";
+}
+
+const char *jvc_format::extensions() const
+{
+ return "jvc,dsk";
+}
+
+bool jvc_format::parse_header(io_generic *io, int &header_size, int &tracks, int &heads, int &sectors, int &sector_size, int &base_sector_id)
+{
+ UINT64 size = io_generic_size(io);
+ header_size = size % 256;
+ UINT8 header[5];
+
+ if (header_size > 0)
+ io_generic_read(io, header, 0, header_size);
+
+ if (header_size > 5)
+ return false;
+
+ // default values
+ heads = 1;
+ sectors = 18;
+ sector_size = 256;
+ base_sector_id = 1;
+
+ switch (header_size)
+ {
+ case 5: emu_fatalerror("jvc_format: sector attribute flag unsupported\n");
+ break;
+ case 4: base_sector_id = header[3];
+ // no break
+ case 3: sector_size = 128 << header[2];
+ // no break
+ case 2: heads = header[1];
+ // no break
+ case 1: sectors = header[0];
+ // no break
+ case 0: tracks = (size - header_size) / sector_size / sectors;
+ break;
+ }
+
+ return tracks * heads * sectors * sector_size == (size - header_size);
+}
+
+int jvc_format::identify(io_generic *io, UINT32 form_factor)
+{
+ int header_size, tracks, heads, sectors, sector_size, sector_base_id;
+ return parse_header(io, header_size, tracks, heads, sectors, sector_size, sector_base_id) ? 50 : 0;
+}
+
+bool jvc_format::load(io_generic *io, UINT32 form_factor, floppy_image *image)
+{
+ int header_size, track_count, head_count, sector_count, sector_size, sector_base_id;
+
+ if (!parse_header(io, header_size, track_count, head_count, sector_count, sector_size, sector_base_id))
+ return false;
+
+ // safety check
+ if (sector_count * sector_size > 10000)
+ emu_fatalerror("jvc_format: incorrect track layout\n");
+
+ int file_offset = header_size;
+
+ for (int track = 0; track < track_count; track++)
+ {
+ for (int head = 0; head < head_count ; head++)
+ {
+ desc_pc_sector sectors[256];
+ UINT8 sector_data[10000];
+ int sector_offset = 0;
+
+ for (int i = 0; i < sector_count; i++)
+ {
+ sectors[i].track = track;
+ sectors[i].head = head;
+ sectors[i].sector = sector_base_id + i;
+ sectors[i].actual_size = sector_size;
+ sectors[i].size = sector_size >> 8;
+ sectors[i].deleted = false;
+ sectors[i].bad_crc = false;
+ sectors[i].data = &sector_data[sector_offset];
+
+ io_generic_read(io, sectors[i].data, file_offset, sector_size);
+
+ sector_offset += sector_size;
+ file_offset += sector_size;
+ }
+
+ build_wd_track_mfm(track, head, image, 100000, sector_count, sectors, 22, 32, 24);
+ }
+ }
+
+ return true;
+}
+
+bool jvc_format::save(io_generic *io, floppy_image *image)
+{
+ UINT8 bitstream[500000/8];
+ UINT8 sector_data[50000];
+ desc_xs sectors[256];
+ UINT64 file_offset = 0;
+
+ int track_count, head_count;
+ image->get_actual_geometry(track_count, head_count);
+
+ // we'll write a header if the disk is two-sided
+ if (head_count == 2)
+ {
+ UINT8 header[2];
+ header[0] = 18;
+ header[1] = 2;
+ io_generic_write(io, header, file_offset, sizeof(header));
+ file_offset += sizeof(header);
+ }
+
+ // write disk data
+ for (int track = 0; track < track_count; track++)
+ {
+ for (int head = 0; head < head_count; head++)
+ {
+ int track_size;
+ generate_bitstream_from_track(track, head, 2000, bitstream, track_size, image);
+ extract_sectors_from_bitstream_mfm_pc(bitstream, track_size, sectors, sector_data, sizeof(sector_data));
+
+ for (int i = 0; i < 18; i++)
+ {
+ if (sectors[1 + i].size != 256)
+ emu_fatalerror("jvc_format: invalid sector size: %d\n", sectors[1 + i].size);
+
+ io_generic_write(io, sectors[1 + i].data, file_offset, sectors[1 + i].size);
+ file_offset += sectors[1 + i].size;
+ }
+ }
+ }
+
+ return true;
+}
+
+bool jvc_format::supports_save() const
+{
+ return true;
+}
+
+const floppy_format_type FLOPPY_JVC_FORMAT = &floppy_image_format_creator<jvc_format>;