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-rw-r--r--src/lib/formats/fdd_dsk.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/src/lib/formats/fdd_dsk.c b/src/lib/formats/fdd_dsk.c
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index 00000000000..9390449add2
--- /dev/null
+++ b/src/lib/formats/fdd_dsk.c
@@ -0,0 +1,149 @@
+// license:BSD-3-Clause
+// copyright-holders:etabeta
+/*********************************************************************
+
+ 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 "emu.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];
+ UINT32 track_sizes[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;
+ track_sizes[track] = curr_track_size;
+ }
+
+ 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>;