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author Nigel Barnes <Pernod70@users.noreply.github.com>2015-11-15 02:38:06 +0000
committer Nigel Barnes <Pernod70@users.noreply.github.com>2015-11-15 02:38:06 +0000
commit5d004af6c92344b8a8f007b695f0203e6414e168 (patch)
treef4dee2f622739423fb34725227042371f9736cdb /src/lib/formats/fsd_dsk.cpp
parent1c79e53fbc4280c342c77a0fe3a2175eadfdfc4e (diff)
bbc: preliminary support for FSD format.
Diffstat (limited to 'src/lib/formats/fsd_dsk.cpp')
-rw-r--r--src/lib/formats/fsd_dsk.cpp180
1 files changed, 180 insertions, 0 deletions
diff --git a/src/lib/formats/fsd_dsk.cpp b/src/lib/formats/fsd_dsk.cpp
new file mode 100644
index 00000000000..c5820c7ef66
--- /dev/null
+++ b/src/lib/formats/fsd_dsk.cpp
@@ -0,0 +1,180 @@
+// license:BSD-3-Clause
+// copyright-holders:Nigel Barnes
+/***************************************************************************
+
+ BBC Micro 8271 protected disk image format
+
+ Disk image format
+
+***************************************************************************/
+
+#include "emu.h"
+#include "fsd_dsk.h"
+
+
+/*********************************************************************
+
+ BBC Micro 8271 protected disk image format
+
+ Header:
+ =======
+ Identifier: "FSD" string literal 3 bytes
+ Creator: 5 bytes; date of creation/author
+ Title: Character string (unlimited length; may contain any but null)
+ Title_End: 0x00 byte literal 1 byte
+ Num_Tr: xx 1 byte, number of tracks
+
+ For each track
+ ==============
+ track_num: 1 byte
+ num_sec: 1 byte (00 == unformatted)
+ readable: 1 byte (00 == unreadable, ff ==readable)
+
+ If readable:
+ For each sector
+ ===============
+ Track_ID: 1 byte
+ Head_number: 1 byte
+ Sector_ID: 1 byte
+ reported_size: 1 byte (2^{7+x}; 0 ==>128, 1 ==> 256, 2==>512, 3==>1024 etc)
+ real_size: 1 byte (2^{7+x})
+ error_code: 1 byte (0==No Error, &20==Deleted Data; &0E = Data CRC Error)
+ data: <real_size> bytes
+ Note that error_code matches the OSWORD &7F result byte
+
+ If unreadable:
+ Track_ID: 1 byte
+ Head_number: 1 byte
+ Sector_ID: 1 byte
+ reported_size: 1 byte
+
+ Decoding of the "creator" 5 byte field:
+ =======================================
+ (byte1 byte2 byte3 byte4 byte5)
+
+ Date_DD = (byte1 AND &F8)/8
+ Date_MM = (byte3 AND &0F)
+ Date_YYYY = (byte1 AND &07)*256+byte2
+ Creator_ID = (byte3 AND &F0)/16
+ Release_num = ((byte5 AND &C0)/64)*256 + byte4
+
+*********************************************************************/
+
+fsd_format::fsd_format()
+{
+}
+
+const char *fsd_format::name() const
+{
+ return "fsd";
+}
+
+const char *fsd_format::description() const
+{
+ return "BBC Micro 8271 protected disk image";
+}
+
+const char *fsd_format::extensions() const
+{
+ return "fsd";
+}
+
+bool fsd_format::supports_save() const
+{
+ return false;
+}
+
+int fsd_format::identify(io_generic *io, UINT32 form_factor)
+{
+ UINT8 h[3];
+
+ io_generic_read(io, h, 0, 3);
+ if (memcmp(h, "FSD", 3) == 0) {
+ return 100;
+ }
+ return 0;
+}
+
+bool fsd_format::load(io_generic *io, UINT32 form_factor, floppy_image *image)
+{
+ UINT64 size = io_generic_size(io);
+ dynamic_buffer img(size);
+ io_generic_read(io, &img[0], 0, size);
+
+ UINT64 pos;
+ std::string title;
+ for(pos=8; pos < size && img[pos] != NULL; pos++)
+ title += char(img[pos]);
+ pos++;
+
+ if(pos >= size)
+ return false;
+
+ //popmessage("Loading image of '%s'\n", title);
+
+ desc_pc_sector sects[10];
+ UINT8 total_tracks = img[pos++];
+ UINT8 tnum, hnum, snum, ssize, error;
+
+ hnum = 0;
+ //osd_printf_verbose("%d Tracks\n", total_tracks+1);
+ //osd_printf_verbose("Tr.# No.S Sec.# Tr.ID Head# SecID IDsiz REsiz Error\n");
+ for(int curr_track=0; curr_track <= total_tracks; curr_track++)
+ {
+ UINT8 track = img[pos++];
+ UINT8 spt = img[pos++];
+ //osd_printf_verbose("%x %x\n", track, spt);
+ if (spt > 0) // formatted
+ {
+ UINT8 readable = img[pos++];
+ for (int i = 0; i < spt; i++)
+ {
+ tnum = img[pos++]; // logical track
+ hnum = img[pos++]; // head number
+ snum = img[pos++]; // logical sector
+ ssize = img[pos++]; // reported size
+ sects[i].track = tnum;
+ sects[i].head = hnum;
+ sects[i].sector = snum;
+ sects[i].size = ssize;
+ if (readable == 0xff)
+ {
+ sects[i].actual_size = 1 << (img[pos++] + 7);
+ error = img[pos++];
+ sects[i].deleted = (error & 0x20) == 0x20;
+ sects[i].bad_crc = (error & 0x0e) == 0x0e;
+ sects[i].data = &img[pos];
+ pos += sects[i].actual_size;
+ //osd_printf_verbose("Read %x %x %x %x %x %x %x\n", i, sects[i].track, sects[i].head, sects[i].sector, sects[i].size, sects[i].actual_size, error);
+ }
+ else
+ {
+ throw emu_fatalerror("fsd_format: Unsupported unreadable sector on track %d sector %d head %d", track, i, hnum);
+
+ // Unreadable sectors not supported!!
+ //sects[i].track = track;
+ //sects[i].head = 0;
+ //sects[i].sector = i;
+ //sects[i].size = 0;
+ //sects[i].actual_size = 0;
+ //sects[i].deleted = false;
+ //sects[i].bad_crc = false;
+ //sects[i].data = NULL;
+ //osd_printf_verbose("Unread %x %x %x %x %x %x %x\n", i, sects[i].track, sects[i].head, sects[i].sector, sects[i].size, sects[i].actual_size, 0);
+ }
+ }
+ }
+ else // unformatted
+ {
+ sects[0].track = curr_track;
+ sects[0].head = hnum;
+ sects[0].sector = 0;
+ sects[0].size = 0;
+ //osd_printf_verbose("Unform %x %x %x %x %x %x %x\n", 0, sects[0].track, sects[0].head, sects[0].sector, sects[0].size, sects[0].actual_size, 0);
+ }
+ build_wd_track_fm(curr_track, hnum, image, 50000, spt, sects, 10, 40, 10);
+ }
+ return true;
+}
+
+const floppy_format_type FLOPPY_FSD_FORMAT = &floppy_image_format_creator<fsd_format>;