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+// license:BSD-3-Clause
+// copyright-holders:Sergey Svishchev
+/*********************************************************************
+
+ formats/ibmxdf_dsk.cpp
+
+ IBM Extended Density Format
+
+ References:
+ - http://www.os2museum.com/wp/the-xdf-diskette-format/
+ - https://fdutils.linux.lu/Fdutils.html#SEC47 and xdfcopy.c
+
+ Mapping XDF disk image to physical sectors on a 3.5" disk:
+
+ First track uses standard 512-byte sectors:
+ - lbn 0 (boot sector) = 0.129 (head.sector)
+ - lbn 1-11 (FAT) = 0.130-0.139, then 1.129
+ - lbn 12-19 (aux FS) = 0.1-0.8
+ - lbn 20-22 = padding, not written to disk
+ - lbn 23-36 (root directory) = 1.130-1.143
+ - lbn 37-41 = padding, not written to disk
+ - lbn 42-45 (start of data area) = 1.144-1.147
+
+ All other tracks use mixed size sectors, sequenced like so:
+ 0.131, 0.132, 1.134, 0.130, 1.130, 0.134, 1.132, 1.131
+
+ To do:
+ - 5.25 HD and 3.5 ED formats
+ - replace magic numbers
+
+*********************************************************************/
+
+#include "ibmxdf_dsk.h"
+#include "imageutl.h"
+
+#include "ioprocs.h"
+
+
+ibmxdf_format::ibmxdf_format() : wd177x_format(formats)
+{
+}
+
+const char *ibmxdf_format::name() const noexcept
+{
+ return "ibmxdf";
+}
+
+const char *ibmxdf_format::description() const noexcept
+{
+ return "IBM XDF disk image";
+}
+
+const char *ibmxdf_format::extensions() const noexcept
+{
+ return "xdf,img";
+}
+
+int ibmxdf_format::identify(util::random_read &io, uint32_t form_factor, const std::vector<uint32_t> &variants) const
+{
+ int type = find_size(io, form_factor, variants);
+
+ if (type != -1)
+ return FIFID_SIZE;
+ return 0;
+}
+
+int ibmxdf_format::find_size(util::random_read &io, uint32_t form_factor, const std::vector<uint32_t> &variants) const
+{
+ uint64_t size;
+ if (io.length(size))
+ return -1;
+
+ if (size != 1884160)
+ return -1;
+
+ return 0;
+}
+
+int ibmxdf_format::get_image_offset(const format &f, int head, int track) const
+{
+ return (2 * track) * compute_track_size(formats[0]);
+}
+
+const wd177x_format::format &ibmxdf_format::get_track_format(const format &f, int head, int track) const
+{
+ int n = -1;
+
+ for (int i = 0; formats[i].form_factor; i++) {
+ if (&formats[i] == &f) {
+ n = i;
+ break;
+ }
+ }
+
+ if (n < 0) {
+ LOG_FORMATS("Error format not found\n");
+ return f;
+ }
+
+ if (head >= f.head_count) {
+ LOG_FORMATS("Error invalid head %d\n", head);
+ return f;
+ }
+
+ if (track >= f.track_count) {
+ LOG_FORMATS("Error invalid track %d\n", track);
+ return f;
+ }
+
+ if (track > 0) {
+ if (head == 1) {
+ const format &fh1 = formats_head1[n];
+ if (!fh1.form_factor) {
+ LOG_FORMATS("Error expected a head 1 format\n");
+ return f;
+ }
+ return fh1;
+ }
+ return f;
+ }
+
+ // Track 0
+
+ if (head == 1) {
+ const format &fh1t0 = formats_head1_track0[n];
+ if (fh1t0.form_factor) {
+ return fh1t0;
+ }
+ const format &fh1 = formats_head1[n];
+ if (fh1.form_factor) {
+ return fh1;
+ }
+ LOG_FORMATS("Error expected a head 1 format\n");
+ return f;
+ }
+
+ // Head 0
+
+ const format &ft0 = formats_track0[n];
+ if (ft0.form_factor) {
+ return ft0;
+ }
+
+ return f;
+}
+
+
+// Unverified gap sizes
+const ibmxdf_format::format ibmxdf_format::formats[] = {
+ {
+ floppy_image::FF_35, floppy_image::DSHD, floppy_image::MFM,
+ 1000, 4, 80, 2, 0, { 1024, 512, 2048, 8192 }, -1, { 131, 130, 132, 134 }, 50, 22, 74
+ },
+ {}
+};
+
+const ibmxdf_format::format ibmxdf_format::formats_head1[] = {
+ {
+ floppy_image::FF_35, floppy_image::DSHD, floppy_image::MFM,
+ 1000, 4, 80, 2, 0, { 2048, 512, 1024, 8192 }, -1, { 132, 130, 131, 134 }, 50, 22, 74
+ },
+ {}
+};
+
+const ibmxdf_format::format ibmxdf_format::formats_track0[] = {
+ {
+ floppy_image::FF_35, floppy_image::DSHD, floppy_image::MFM,
+ 1000, 19, 80, 2, 512, {}, -1, { 1, 138, 129, 139, 130, 2, 131, 3, 132, 4, 133, 5, 134, 6, 135, 7, 136, 8, 137 }, 50, 22, 74
+ },
+ {}
+};
+
+const ibmxdf_format::format ibmxdf_format::formats_head1_track0[] = {
+ {
+ floppy_image::FF_35, floppy_image::DSHD, floppy_image::MFM,
+ 1000, 19, 80, 2, 512, {}, -1, { 144, 135, 145, 136, 146, 137, 147, 138, 129, 139, 130, 140, 131, 141, 132, 142, 133, 143, 134 }, 50, 22, 74
+ },
+ {}
+};
+
+bool ibmxdf_format::load(util::random_read &io, uint32_t form_factor, const std::vector<uint32_t> &variants, floppy_image &image) const
+{
+ int type = find_size(io, form_factor, variants);
+ if(type == -1)
+ return false;
+
+ const format &f = formats[type];
+
+ for(int track = 0; track < f.track_count; track++) {
+ for(int head = 0; head < f.head_count; head++) {
+ uint8_t sectdata[23 * 2 * 512]; // XXX magic
+ desc_s sectors[40];
+ floppy_image_format_t::desc_e *desc;
+ int current_size;
+ int end_gap_index;
+ const format &tf = get_track_format(f, head, track);
+
+ desc = get_desc_mfm(tf, current_size, end_gap_index);
+
+ int total_size = 200000000/tf.cell_size;
+ int remaining_size = total_size - current_size;
+ if(remaining_size < 0) {
+ osd_printf_error("ibmxdf_format: Incorrect track layout, max_size=%d, current_size=%d\n", total_size, current_size);
+ return false;
+ }
+
+ // Fixup the end gap
+ desc[end_gap_index].p2 = remaining_size / 16;
+ desc[end_gap_index + 1].p2 = remaining_size & 15;
+ desc[end_gap_index + 1].p1 >>= 16-(remaining_size & 15);
+
+ desc[16].p1 = get_track_dam_mfm(tf, head, track);
+
+ build_sector_description(tf, sectdata, sectors, track, head);
+ int const track_size = compute_track_size(f) * 2; // read both sides at once
+ /*auto const [err, actual] =*/ read_at(io, get_image_offset(f, head, track), sectdata, track_size); // FIXME: check for errors and premature EOF
+ generate_track(desc, track, head, sectors, tf.sector_count, total_size, image);
+ }
+ }
+
+ image.set_variant(f.variant);
+
+ return true;
+}
+
+static const int offsets[2][4] = { { 0, 11264, 1024, 12288 }, { 20480, 11776, 22528, 3072 } }; // XXX magic
+
+void ibmxdf_format::build_sector_description(const format &f, uint8_t *sectdata, desc_s *sectors, int track, int head) const
+{
+ switch (track)
+ {
+ case 0:
+ if (head == 0) {
+ for(int i=0; i<f.sector_count; i++) {
+ if (f.per_sector_id[i] < 129) // aux fs
+ sectors[i].data = sectdata + f.sector_base_size * (f.per_sector_id[i] + 11);
+ else
+ sectors[i].data = sectdata + f.sector_base_size * (f.per_sector_id[i] - 129);
+ sectors[i].size = f.sector_base_size;
+ sectors[i].sector_id = f.per_sector_id[i];
+ }
+ }
+ else {
+ for(int i=0; i<f.sector_count; i++) {
+ if (f.per_sector_id[i] == 129)
+ sectors[i].data = sectdata + f.sector_base_size * 11;
+ else if (f.per_sector_id[i] < 144)
+ sectors[i].data = sectdata + f.sector_base_size * (f.per_sector_id[i] - 130 + 23);
+ else // skip 5 sectors marked bad in the FAT
+ sectors[i].data = sectdata + f.sector_base_size * (f.per_sector_id[i] - 130 + 28);
+ sectors[i].size = f.sector_base_size;
+ sectors[i].sector_id = f.per_sector_id[i];
+ }
+ }
+ break;
+
+ default:
+ for(int i=0; i<f.sector_count; i++) {
+ sectors[i].data = sectdata + offsets[head][i];
+ sectors[i].size = f.per_sector_size[i];
+ sectors[i].sector_id = f.per_sector_id[i];
+ }
+ break;
+ }
+}
+
+const ibmxdf_format FLOPPY_IBMXDF_FORMAT;
+