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-rw-r--r--src/lib/formats/m20_dsk.cpp84
1 files changed, 84 insertions, 0 deletions
diff --git a/src/lib/formats/m20_dsk.cpp b/src/lib/formats/m20_dsk.cpp
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+// license:BSD-3-Clause
+// copyright-holders:Olivier Galibert
+/*********************************************************************
+
+ formats/m20_dsk.c
+
+ Olivetti M20 floppy-disk images
+
+ Track 0/head 0 is FM, 128 byte sectors. The rest is MFM,
+ 256 byte sectors.
+ In image files the sectors of track 0/sector 0 are 256 bytes
+ long to simplify access. Only the first half of these sectors
+ contain image data.
+
+*********************************************************************/
+
+#include "m20_dsk.h"
+
+m20_format::m20_format()
+{
+}
+
+const char *m20_format::name() const
+{
+ return "m20";
+}
+
+const char *m20_format::description() const
+{
+ return "M20 disk image";
+}
+
+const char *m20_format::extensions() const
+{
+ return "img";
+}
+
+bool m20_format::supports_save() const
+{
+ return false;
+}
+
+int m20_format::identify(io_generic *io, UINT32 form_factor)
+{
+ if(io_generic_size(io) == 286720)
+ return 50;
+ return 0;
+}
+
+bool m20_format::load(io_generic *io, UINT32 form_factor, floppy_image *image)
+{
+ for(int track = 0; track < 35; track++)
+ for(int head = 0; head < 2; head ++) {
+ bool mfm = track || head;
+ desc_pc_sector sects[16];
+ UINT8 sectdata[16*256];
+ io_generic_read(io, sectdata, 16*256*(track*2+head), 16*256);
+ for(int i=0; i<16; i++) {
+ int j = i/2 + (i & 1 ? 0 : 8);
+ sects[i].track = track;
+ sects[i].head = head;
+ sects[i].sector = j+1;
+ sects[i].size = mfm ? 1 : 0;
+ sects[i].actual_size = mfm ? 256 : 128;
+ sects[i].data = sectdata + 256*j;
+ sects[i].deleted = false;
+ sects[i].bad_crc = false;
+ }
+
+ if(mfm)
+ build_wd_track_mfm(track, head, image, 100000, 16, sects, 50, 32, 22);
+ else
+ build_wd_track_fm(track, head, image, 50000, 16, sects, 24, 16, 11);
+ }
+
+ return true;
+}
+
+bool m20_format::save(io_generic *io, floppy_image *image)
+{
+ return false;
+}
+
+const floppy_format_type FLOPPY_M20_FORMAT = &floppy_image_format_creator<m20_format>;