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Fix 5.25 track stepping bug. The only test case is that Mabel's Mansion now boots.

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This commit is contained in:
Nick Westgate 2015-02-02 09:51:26 +00:00
parent 753d907315
commit fa8313dd1c
1 changed files with 8 additions and 29 deletions
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37
src/iwm.c
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@ -573,56 +573,35 @@ iwm525_phase_change(int drive, int phase)
{ {
Disk *dsk; Disk *dsk;
int qtr_track; int qtr_track;
int last_phase;
int phase_up;
int phase_down;
int delta; int delta;
phase_up = (phase - 1) & 3;
phase_down = (phase + 1) & 3;
dsk = &(iwm.drive525[drive]); dsk = &(iwm.drive525[drive]);
last_phase = dsk->last_phase;
qtr_track = dsk->cur_qtr_track; qtr_track = dsk->cur_qtr_track;
int half_track = qtr_track >> 1;
delta = 0; delta = 0;
if(last_phase == phase_up) { if (iwm.iwm_phase[(half_track + 1) & 3])
delta = 2; delta += 2;
last_phase = phase; if (iwm.iwm_phase[(half_track + 3) & 3])
} else if(last_phase == phase_down) { delta -= 2;
delta = -2;
last_phase = phase;
}
qtr_track += delta; qtr_track += delta;
if(qtr_track < 0) { if(qtr_track < 0) {
printf("GRIND...GRIND...GRIND\n"); printf("GRIND...");
qtr_track = 0; qtr_track = 0;
last_phase = 0;
} }
if(qtr_track > 4*34) { if(qtr_track > 4*34) {
printf("Disk arm moved past track 34, moving it back\n"); printf("Disk arm moved past track 34, moving it back\n");
qtr_track = 4*34; qtr_track = 4*34;
last_phase = 0;
} }
iwm_move_to_track(dsk, qtr_track); iwm_move_to_track(dsk, qtr_track);
dsk->last_phase = last_phase; iwm_printf("Moving drive to qtr track: %04x (trk:%d.%02d), %d, %d, "
iwm_printf("Moving drive to qtr track: %04x (trk:%d.%02d), %d, %d, %d, "
"%d %d %d %d\n", qtr_track, qtr_track>>2, 25*(qtr_track & 3), "%d %d %d %d\n", qtr_track, qtr_track>>2, 25*(qtr_track & 3),
phase, delta, last_phase, iwm.iwm_phase[0], phase, delta, iwm.iwm_phase[0],
iwm.iwm_phase[1], iwm.iwm_phase[2], iwm.iwm_phase[3]); iwm.iwm_phase[1], iwm.iwm_phase[2], iwm.iwm_phase[3]);
/* sanity check stepping algorithm */
if((qtr_track & 7) == 0) {
/* check for just access phase 0 */
if(last_phase != 0 ) {
halt_printf("last_phase: %d!\n", last_phase);
}
}
} }
int int