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Diffstat (limited to 'src/lib/formats/fdd_dsk.cpp')
-rw-r--r-- | src/lib/formats/fdd_dsk.cpp | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/src/lib/formats/fdd_dsk.cpp b/src/lib/formats/fdd_dsk.cpp new file mode 100644 index 00000000000..2c564e3e306 --- /dev/null +++ b/src/lib/formats/fdd_dsk.cpp @@ -0,0 +1,148 @@ +// license:BSD-3-Clause +// copyright-holders:Fabio Priuli +/********************************************************************* + + formats/fdd_dsk.h + + PC98 FDD disk images + + 0xC3FC header, followed by track data + Sector map starts at offset 0xDC, with 12bytes for each sector + + Each entry of the sector map has the following structure + - 0x0 = track number (if 0xff the sector/track is unformatted/unused) + - 0x1 = head number + - 0x2 = sector number + - 0x3 = sector size (128 << this byte) + - 0x4 = fill byte. if it's not 0xff, then this sector in the original + disk consisted of this single value repeated for the whole + sector size, and the sector is skipped in the .fdd file. + if it's 0xff, then this sector is wholly contained in the .fdd + file + - 0x5 = ?? + - 0x6 = ?? + - 0x7 = ?? + - 0x8-0x0b = absolute offset of the data for this sector, or 0xfffffff + if the sector was skipped in the .fdd (and it has to be + filled with the value at 0x4) + + TODO: + - Investigate remaining sector map bytes (maybe related to protections?) + +*********************************************************************/ + +#include <assert.h> + +#include "fdd_dsk.h" + +fdd_format::fdd_format() +{ +} + +const char *fdd_format::name() const +{ + return "fdd"; +} + +const char *fdd_format::description() const +{ + return "FDD disk image"; +} + +const char *fdd_format::extensions() const +{ + return "fdd"; +} + +int fdd_format::identify(io_generic *io, UINT32 form_factor) +{ + UINT8 h[7]; + io_generic_read(io, h, 0, 7); + + if (strncmp((const char *)h, "VFD1.0", 6) == 0) + return 100; + + return 0; +} + +bool fdd_format::load(io_generic *io, UINT32 form_factor, floppy_image *image) +{ + UINT8 hsec[0x0c]; + + // sector map + UINT8 num_secs[160]; + UINT8 tracks[160 * 26]; + UINT8 heads[160 * 26]; + UINT8 secs[160 * 26]; + UINT8 fill_vals[160 * 26]; + UINT32 sec_offs[160 * 26]; + UINT8 sec_sizes[160 * 26]; + + int pos = 0xdc; + + for (int track = 0; track < 160; track++) + { + int curr_num_sec = 0, curr_track_size = 0; + for (int sect = 0; sect < 26; sect++) + { + // read sector map for this sector + io_generic_read(io, hsec, pos, 0x0c); + pos += 0x0c; + + if (hsec[0] == 0xff) // unformatted/unused sector + continue; + + tracks[(track * 26) + sect] = hsec[0]; + heads[(track * 26) + sect] = hsec[1]; + secs[(track * 26) + sect] = hsec[2]; + sec_sizes[(track * 26) + sect] = hsec[3]; + fill_vals[(track * 26) + sect] = hsec[4]; + sec_offs[(track * 26) + sect] = LITTLE_ENDIANIZE_INT32(*(UINT32 *)(hsec + 0x08)); + + curr_track_size += (128 << hsec[3]); + curr_num_sec++; + } + num_secs[track] = curr_num_sec; + } + + int cell_count = form_factor == floppy_image::FF_35 ? 200000 : 166666; + desc_pc_sector sects[256]; + UINT8 sect_data[65536]; + int cur_sec_map = 0, sector_size; + + for (int track = 0; track < 160; track++) + { + int cur_pos = 0; + for (int i = 0; i < num_secs[track]; i++) + { + cur_sec_map = track * 26 + i; + sector_size = 128 << sec_sizes[cur_sec_map]; + + if (sec_offs[cur_sec_map] == 0xffffffff) + memset(sect_data + cur_pos, fill_vals[cur_sec_map], sector_size); + else + io_generic_read(io, sect_data + cur_pos, sec_offs[cur_sec_map], sector_size); + + sects[i].track = tracks[cur_sec_map]; + sects[i].head = heads[cur_sec_map]; + sects[i].sector = secs[cur_sec_map]; + sects[i].size = sec_sizes[cur_sec_map]; + sects[i].actual_size = sector_size; + sects[i].deleted = false; + sects[i].bad_crc = false; + sects[i].data = sect_data + cur_pos; + cur_pos += sector_size; + } + + build_pc_track_mfm(track / 2, track % 2, image, cell_count, num_secs[track], sects, calc_default_pc_gap3_size(form_factor, (128 << sec_sizes[track * 26]))); + } + + return true; +} + +bool fdd_format::supports_save() const +{ + return false; +} + +const floppy_format_type FLOPPY_FDD_FORMAT = &floppy_image_format_creator<fdd_format>; |