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ti99: Fixed another issue with double stepping.

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This commit is contained in:
Michael Zapf 2016-08-25 19:26:46 +02:00
parent f4db841a2e
commit 596b04dd5c
2 changed files with 44 additions and 19 deletions
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57
src/lib/formats/ti99_dsk.cpp
View File

@ -99,8 +99,8 @@ bool ti99_floppy_format::load(io_generic *io, UINT32 form_factor, floppy_image *
int cell_size = 0;
int sector_count = 0;
int heads = 0;
int tracks = 0;
determine_sizes(io, cell_size, sector_count, heads, tracks);
int log_track_count = 0;
determine_sizes(io, cell_size, sector_count, heads, log_track_count);
if (cell_size == 0) return false;
@ -112,29 +112,49 @@ bool ti99_floppy_format::load(io_generic *io, UINT32 form_factor, floppy_image *
int file_size = io_generic_size(io);
int track_size = get_track_size(cell_size, sector_count);
int track_count = tracks;
if (tracks==0) track_count = file_size / (track_size*heads);
if (TRACE) osd_printf_info("ti99_dsk: track count = %d\n", track_count);
// Problem: If the disk is improperly formatted, the track count will be
// wrong. For instance, a disk could be reformatted to single-side.
// We assume there is no disk with single side format beyond 40 tracks.
if ((heads==1) && (file_size > track_size*40))
heads = 2;
if (track_count > maxtrack)
int phys_track_count = file_size / (track_size*heads);
// Some disks are known to have an incomplete header.
// PASCAL disks have a track count of 0.
if (log_track_count==0) log_track_count = phys_track_count;
if (TRACE) osd_printf_info("ti99_dsk: logical tracks = %d, physical tracks = %d\n", log_track_count, phys_track_count);
if (phys_track_count > maxtrack)
{
osd_printf_error("ti99_dsk: Floppy disk has too many tracks for this drive.\n");
return false;
}
bool doubletracks = (track_count * 2 <= maxtrack);
// Is this the first time that this disk is read in an 80-track drive?
bool double_step = ((log_track_count * 2) <= maxtrack);
bool first_time_double = ((phys_track_count * 2) <= maxtrack);
if (doubletracks) osd_printf_warning("ti99_dsk: 40-track image in an 80-track drive. On save, image size will double.\n");
if (first_time_double)
{
osd_printf_warning("ti99_dsk: 40-track image in an 80-track drive. On save, image size will double.\n");
}
int acttrack;
// Read the image
for(int head=0; head < heads; head++)
for (int head=0; head < heads; head++)
{
for(int track=0; track < track_count; track++)
for (int track=0; track < phys_track_count; track++)
{
load_track(io, trackdata, head, track, sector_count, track_count, cell_size);
if (double_step && !first_time_double) acttrack = track/2;
else acttrack = track;
if (doubletracks)
load_track(io, trackdata, head, track, acttrack, sector_count, phys_track_count, cell_size);
if (first_time_double)
{
// Create two tracks from each medium track. This reflects the
// fact that the drive head will find the same data after
@ -160,6 +180,7 @@ bool ti99_floppy_format::load(io_generic *io, UINT32 form_factor, floppy_image *
}
}
}
return true;
}
@ -885,8 +906,11 @@ int ti99_sdf_format::get_track_size(int cell_size, int sector_count)
Load a SDF image track. Essentially, we want to end up in the same
kind of track image as with the TDF, so the easiest thing is to produce
a TDF image track from the sectors and process them as if it came from TDF.
acttrack is the actual track when double stepping is used and changes
every two physical tracks.
*/
void ti99_sdf_format::load_track(io_generic *io, UINT8 *trackdata, int head, int track, int sectorcount, int trackcount, int cellsize)
void ti99_sdf_format::load_track(io_generic *io, UINT8 *trackdata, int head, int track, int acttrack, int sectorcount, int trackcount, int cellsize)
{
bool fm = (cellsize==4000);
int tracksize = sectorcount * SECTOR_SIZE;
@ -906,7 +930,7 @@ void ti99_sdf_format::load_track(io_generic *io, UINT8 *trackdata, int head, int
memset(trackdata, 0x00, 9216);
int secno = 0;
secno = (track * skew) % sectorcount;
secno = (acttrack * skew) % sectorcount;
// Gap 1
int gap1 = fm? 16 : 40;
@ -928,7 +952,7 @@ void ti99_sdf_format::load_track(io_generic *io, UINT8 *trackdata, int head, int
trackdata[position++] = 0xfe; // IDAM / ident
// Header
trackdata[position++] = track;
trackdata[position++] = acttrack;
trackdata[position++] = head;
trackdata[position++] = i;
trackdata[position++] = 1;
@ -1112,8 +1136,9 @@ void ti99_tdf_format::determine_sizes(io_generic *io, int& cell_size, int& secto
/*
For TDF this just amounts to loading the track from the image file.
acttrack is not used here, since the file contains the track data.
*/
void ti99_tdf_format::load_track(io_generic *io, UINT8 *trackdata, int head, int track, int sectorcount, int trackcount, int cellsize)
void ti99_tdf_format::load_track(io_generic *io, UINT8 *trackdata, int head, int track, int acttrack, int sectorcount, int trackcount, int cellsize)
{
int offset = ((trackcount * head) + track) * get_track_size(cellsize, 0);
io_generic_read(io, trackdata, offset, get_track_size(cellsize, 0));

6
src/lib/formats/ti99_dsk.h
View File

@ -31,7 +31,7 @@ protected:
virtual void determine_sizes(io_generic *io, int& cell_size, int& sector_count, int& heads, int& tracks) =0;
virtual int get_track_size(int cell_size, int sector_count) =0;
virtual void load_track(io_generic *io, UINT8 *trackdata, int head, int track, int sectorcount, int trackcount, int cellsize) =0;
virtual void load_track(io_generic *io, UINT8 *trackdata, int head, int track, int acttrack, int sectorcount, int trackcount, int cellsize) =0;
virtual void write_track(io_generic *io, UINT8 *trackdata, int *sector, int track, int head, int maxsect, int maxtrack, int numbytes) =0;
int get_encoding(int cell_size);
@ -60,7 +60,7 @@ private:
void determine_sizes(io_generic *io, int& cell_size, int& sector_count, int& heads, int& tracks) override;
int get_track_size(int cell_size, int sector_count) override;
void write_track(io_generic *io, UINT8 *trackdata, int *sector, int track, int head, int maxsect, int maxtrack, int numbytes) override;
void load_track(io_generic *io, UINT8 *trackdata, int head, int track, int sectorcount, int trackcount, int cellsize) override;
void load_track(io_generic *io, UINT8 *trackdata, int head, int track, int acttrack, int sectorcount, int trackcount, int cellsize) override;
// This format supports single-sided images
int min_heads() override { return 1; }
@ -97,7 +97,7 @@ public:
private:
void determine_sizes(io_generic *io, int& cell_size, int& sector_count, int& heads, int& tracks) override;
void load_track(io_generic *io, UINT8 *trackdata, int head, int track, int sectorcount, int trackcount, int cellsize) override;
void load_track(io_generic *io, UINT8 *trackdata, int head, int track, int acttrack, int sectorcount, int trackcount, int cellsize) override;
void write_track(io_generic *io, UINT8 *trackdata, int *sector, int track, int head, int maxsect, int maxtrack, int numbytes) override;
int get_track_size(int cell_size, int sector_count) override;