// 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 §ors, int §or_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 = §or_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;