// license:BSD-3-Clause // copyright-holders:Fabio Priuli /********************************************************************* formats/dcp_dsk.h PC98 DCP & DCU disk images 0xA2 header, followed by track data header[0] - disk format header[1-0xA1] - track map (1=track used, 0=track unused/unformatted) header[0xA2] - all tracks used? (there seems to be a diff in its usage between DCP and DCU) TODO: - add support for track map. images available for tests were all of type 0x01, with all 154 tracks present. combined with pete_j reporting some images have faulty track map, we need some more test cases to properly handle these disks! *********************************************************************/ #include #include "dcp_dsk.h" dcp_format::dcp_format() { } const char *dcp_format::name() const { return "dcx"; } const char *dcp_format::description() const { return "DCP/DCU disk image"; } const char *dcp_format::extensions() const { return "dcp,dcu"; } int dcp_format::identify(io_generic *io, uint32_t form_factor) { uint64_t size = io_generic_size(io); uint8_t h[0xa2]; int heads, tracks, spt, bps, count_tracks = 0; bool is_hdb = false; io_generic_read(io, h, 0, 0xa2); // First byte is the disk format (see below in load() for details) switch (h[0]) { case 0x01: default: heads = 2; tracks = 77; spt = 8; bps = 1024; break; case 0x02: heads = 2; tracks = 80; spt = 15; bps = 512; break; case 0x03: heads = 2; tracks = 80; spt = 18; bps = 512; break; case 0x04: heads = 2; tracks = 80; spt = 8; bps = 512; break; case 0x05: heads = 2; tracks = 80; spt = 9; bps = 512; break; case 0x08: heads = 2; tracks = 80; spt = 9; bps = 1024; break; case 0x11: is_hdb = true; heads = 2; tracks = 77; spt = 26; bps = 256; break; case 0x19: heads = 2; tracks = 80; spt = 16; bps = 256; break; case 0x21: heads = 2; tracks = 80; spt = 26; bps = 256; break; } // bytes 0x01 to 0xa1 are track map (0x01 if track is used, 0x00 if track is unformatted/unused) for (int i = 1; i < 0xa1; i++) if (h[i]) count_tracks++; // in theory track map should be enough (former check), but some images have it wrong! // hence, if this check fails, we also allow for images with all tracks and wrong track map if (size - 0xa2 == (heads * count_tracks * spt * bps) || size - 0xa2 == (heads * tracks * spt * bps)) return 100; // for disk type 0x11 the head 0 track 0 has 26 sectors of half width, so we need to compensate calculation if (is_hdb && (size - 0xa2 + (0x80 * 26) == (heads * count_tracks * spt * bps) || size - 0xa2 + (0x80 * 26) == (heads * tracks * spt * bps))) return 100; return 0; } bool dcp_format::load(io_generic *io, uint32_t form_factor, floppy_image *image) { uint8_t h[0xa2]; int heads, tracks, spt, bps; bool is_hdb = false; io_generic_read(io, h, 0, 0xa2); // First byte is the disk format: switch (h[0]) { case 0x01: default: //01h: 2HD-8 sector (1.25MB) (BKDSK .HDM) (aka 2HS) //2 sides, 77 tracks, 8 sectors/track, 1024 bytes/sector = 1261568 bytes (360rpm) heads = 2; tracks = 77; spt = 8; bps = 1024; break; case 0x02: //02H: 2HD-15 sector (1.21MB) (BKDSK .HD5) (aka 2HC) //2 sides, 80 tracks, 15 sectors/track, 512 bytes/sector = 1228800 bytes (360rpm) heads = 2; tracks = 80; spt = 15; bps = 512; break; case 0x03: //03H: 2HQ-18 sector (1.44MB) (BKDSK .HD4) (aka 2HDE) //2 sides, 80 tracks, 18 sectors/track, 512 bytes/sector = 1474560 bytes (300rpm) heads = 2; tracks = 80; spt = 18; bps = 512; break; case 0x04: //04H: 2DD-8 sector (640KB) (BKDSK .DD6) //2 sides, 80 tracks, 8 sectors/track, 512 bytes/sector = 655360 bytes (300rpm) heads = 2; tracks = 80; spt = 8; bps = 512; break; case 0x05: //05h: 2DD-9 sector ( 720KB) (BKDSK .DD9) //2 sides, 80 tracks, 9 sectors/track, 512 bytes/sector = 737280 bytes (300rpm) heads = 2; tracks = 80; spt = 9; bps = 512; break; case 0x08: //08h: 2HD-9 sector (1.44MB) //2 sides, 80 tracks, 9 sectors/track, 1024 bytes/sector = 1474560 bytes (300rpm)(??) heads = 2; tracks = 80; spt = 9; bps = 1024; break; case 0x11: //11h: BASIC-2HD (BKDSK .HDB) //Head 0 Track 0 - FM encoding - 26 sectors of 128 bytes = 1 track //Head 1 Track 0 - MFM encoding - 26 sectors of 256 bytes = 1 track //Head 0 Track 1 to Head 1 Track 77 - 26 sectors of 256 bytes = 152 tracks //2 sides, 77 tracks, 26 sectors/track, 256 bytes/sector (except for head 0 track 0) = 1021696 bytes (360rpm) is_hdb = true; heads = 2; tracks = 77; spt = 26; bps = 256; break; case 0x19: //19h: BASIC 2DD (BKDSK .DDB) //2 sides, 80 tracks, 16 sectors/track, 256 bytes/sector = 655360 bytes (300rpm) heads = 2; tracks = 80; spt = 16; bps = 256; break; case 0x21: //21H: 2HD-26 sector //2 sides, 80 tracks, 26 sectors/track, 256 bytes/sector = 1064960 bytes (??rpm)(??) heads = 2; tracks = 80; spt = 26; bps = 256; break; } int cell_count = form_factor == floppy_image::FF_35 ? 200000 : 166666; int ssize; for (ssize = 0; (128 << ssize) < bps; ssize++) {}; desc_pc_sector sects[256]; uint8_t sect_data[65536]; if (!is_hdb) { for (int track = 0; track < tracks; track++) for (int head = 0; head < heads; head++) { io_generic_read(io, sect_data, 0xa2 + bps * spt * (track * heads + head), bps * spt); for (int i = 0; i < spt; i++) { sects[i].track = track; sects[i].head = head; sects[i].sector = i + 1; sects[i].size = ssize; sects[i].actual_size = bps; sects[i].deleted = false; sects[i].bad_crc = false; sects[i].data = sect_data + i * bps; } build_pc_track_mfm(track, head, image, cell_count, spt, sects, calc_default_pc_gap3_size(form_factor, bps)); } } else // FIXME: the code below is untested, because no image was found... there might be some silly mistake in the disk geometry! { // Read Head 0 Track 0 is FM with 26 sectors of 128bytes instead of 256 io_generic_read(io, sect_data, 0xa2, 128 * spt); for (int i = 0; i < spt; i++) { sects[i].track = 0; sects[i].head = 0; sects[i].sector = i + 1; sects[i].size = 0; sects[i].actual_size = 128; sects[i].deleted = false; sects[i].bad_crc = false; sects[i].data = sect_data + i * 128; } build_pc_track_fm(0, 0, image, cell_count, spt, sects, calc_default_pc_gap3_size(form_factor, 128)); // Read Head 1 Track 0 is MFM with 26 sectors of 256bytes io_generic_read(io, sect_data, 0xa2 + 128 * spt, bps * spt); for (int i = 0; i < spt; i++) { sects[i].track = 0; sects[i].head = 1; sects[i].sector = i + 1; sects[i].size = ssize; sects[i].actual_size = bps; sects[i].deleted = false; sects[i].bad_crc = false; sects[i].data = sect_data + i * bps; } build_pc_track_mfm(0, 1, image, cell_count, spt, sects, calc_default_pc_gap3_size(form_factor, bps)); // Read other tracks as usual uint32_t data_offs = 0xa2 + (26 * 0x80) + (26 * 0x100); for (int track = 1; track < tracks; track++) for (int head = 0; head < heads; head++) { io_generic_read(io, sect_data, data_offs + bps * spt * ((track - 1) * heads + head), bps * spt); for (int i = 0; i < spt; i++) { sects[i].track = track; sects[i].head = head; sects[i].sector = i + 1; sects[i].size = ssize; sects[i].actual_size = bps; sects[i].deleted = false; sects[i].bad_crc = false; sects[i].data = sect_data + i * bps; } build_pc_track_mfm(track, head, image, cell_count, spt, sects, calc_default_pc_gap3_size(form_factor, bps)); } } return true; } bool dcp_format::supports_save() const { return false; } const floppy_format_type FLOPPY_DCP_FORMAT = &floppy_image_format_creator;