static floperr_t g64_read_track(floppy_image_legacy *floppy, int head, int track, UINT64 offset, void *buffer, size_t buflen)
{
/*
The following is written into the buffer:
n bytes of track data
1982 bytes of speed zone data
get_track_size() returns n (size of track data)
*/
struct g64dsk_tag *tag = get_tag(floppy);
floperr_t err;
UINT64 track_offset;
UINT16 track_length = tag->track_size[head][track];
// get track offset
err = get_track_offset(floppy, head, track, &track_offset);
if (err)
return err;
if ((head <= tag->heads) && track_offset)
{
if (buflen < track_length) {
printf("G64 track buffer too small: %u < %u!", (UINT32)buflen, track_length);
exit(-1);
}
// read track data
floppy_image_read(floppy, ((UINT8*)buffer), track_offset + 2, track_length); // skip the 2 track length bytes in the beginning of track data
if (tag->speed_zone_offset[head][track] > 3)
{
// read speed block
floppy_image_read(floppy, ((UINT8*)buffer) + track_length, tag->speed_zone_offset[head][track], G64_SPEED_BLOCK_SIZE);
}
else
{
// create a speed block with the same speed zone for the whole track
UINT8 speed = tag->speed_zone_offset[head][track] & 0x03;
UINT8 speed_byte = (speed << 6) | (speed << 4) | (speed << 2) | speed;
memset(((UINT8*)buffer) + track_length, speed_byte, G64_SPEED_BLOCK_SIZE);
}
LOG_FORMATS("G64 side %u track %.1f length %u\n", head, get_dos_track(track), track_length);
}
else
{
// no data for given track, or tried to read side 1
memset(((UINT8*)buffer), 0, buflen);
LOG_FORMATS("G64 side %u track %.1f\n", head, get_dos_track(track));
}
return FLOPPY_ERROR_SUCCESS;
}
static floperr_t g64_read_track(floppy_image *floppy, int head, int track, UINT64 offset, void *buffer, size_t buflen)
{
struct g64dsk_tag *tag = get_tag(floppy);
floperr_t err;
UINT64 track_offset;
UINT16 track_length = 0;
/* get track offset */
err = get_track_offset(floppy, head, track, &track_offset);
if (err)
return err;
if (!head && track_offset)
{
if (buflen < tag->track_size) { printf("G64 track buffer too small: %u!", (UINT32)buflen); exit(-1); }
/* read track */
floppy_image_read(floppy, buffer, track_offset + 2, tag->track_size);
}
else
{
/* set track length to 0 */
memset(buffer, 0, buflen);
}
if (LOG) LOG_FORMATS("G64 track %.1f length %u\n", get_dos_track(track), track_length);
return FLOPPY_ERROR_SUCCESS;
}
static void read_g64_header(floppy_image_legacy *floppy, struct g64dsk_tag *tag, int head, UINT64 &pos)
{
UINT8 header[HEADER_LENGTH];
UINT64 start_pos = pos;
// read header
floppy_image_read(floppy, header, pos, HEADER_LENGTH);
// get version
tag->version = header[8];
if (!head) LOG_FORMATS("G64 version: %u\n", tag->version);
// get number of tracks
tag->tracks = header[9];
LOG_FORMATS("G64 side %u tracks: %u\n", head, tag->tracks);
// get track size
UINT16 track_size = (header[0xb] << 8) | header[0xa];
// get data offsets
pos = 0xc;
for (int i = 0; i < tag->tracks; i++)
{
tag->track_offset[head][i] = pick_integer_le(header, pos, 4);
if (tag->track_offset[head][i])
{
tag->track_offset[head][i] += start_pos;
}
pos += 4;
}
// get speed zone information
UINT32 track_offs = 0;
for (int i = 0; i < tag->tracks; i++)
{
tag->speed_zone_offset[head][i] = pick_integer_le(header, pos, 4);
if (tag->speed_zone_offset[head][i] >= 4)
{
tag->speed_zone_offset[head][i] += start_pos;
}
pos += 4;
tag->track_size[head][i] = g64_get_track_size(floppy, head, i);
if (tag->track_offset[head][i] != 0)
{
LOG_FORMATS("G64 side %u track %.1f offset %05x length %04x ", head, get_dos_track(i), tag->track_offset[head][i], tag->track_size[head][i]);
track_offs = tag->track_offset[head][i];
if (tag->speed_zone_offset[head][i] < 4) {
LOG_FORMATS("speed %u\n", tag->speed_zone_offset[head][i]);
} else {
LOG_FORMATS("speed offset %04x\n", tag->speed_zone_offset[head][i]);
}
}
}
pos = track_offs + 2 + track_size;
}
