| ID | Category [?] | Severity [?] | Reproducibility | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 08458 | Core | Critical (emulation) | Always | Oct 21, 2022, 04:17 | Oct 23, 2022, 09:13 |
| Tester | pnp2084 | View Status | Public | Platform | MAME (Official Binary) |
| Assigned To | pnp2084 | Resolution | Fixed | OS | Windows 10/11 (64-bit) |
| Status [?] | Resolved | Driver | |||
| Version | 0.248 | Fixed in Version | 0.249 | Build | 64-bit |
| Fixed in Git Commit | f5eeb26 | Github Pull Request # | #10454 | ||
| Summary | 08458: trs80l2, trs80m4: WD FDC FM sync incorrect in two places | ||||
| Description |
When wd_fdc.cpp code finds an FM sync mark, in a couple cases (read track and SEARCH_ADDRESS_MARK_HEADER) the "data_reg" value is examined or returned. But this is incorrect: data_reg is only valid after sync has been achieved. This results in the value C7 being examined instead of the correct FE (or FB, FA, F9, F8). Also, not reproduced here, the read track was only looking for FB/F8 marks instead of the four possible DAM marks. |
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| Steps To Reproduce |
The TRSDOS sync problem will occur late in the boot. The DOS READY command prompt will never appear as the emulator endlessly retries a sector on track 17:mame trs80l2 -flop1 trsdos23b.mfi The SuperUtility for model 4 will fail to boot as the code which scans the READ TRACK command result will not find an FE in the (early) part of the track, instead there is an incorrect C7 clock byte in place of the FE. mame trs80m4 -flop1 su4x.mfi |
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| Additional Information | |||||
| Github Commit | |||||
| Flags | |||||
| Regression Version | |||||
| Affected Sets / Systems | trs80l2, trs80m4 | ||||
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Attached Files
|
 fdcsync.zip (222,251 bytes) Oct 21, 2022, 04:17 Uploaded by pnp2084TRSDOS 2.3 and SuperUtility 4 in MFI format
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| fdc_fix.zip (18,695 bytes) Oct 21, 2022, 04:22 Uploaded by pnp2084 FDC fix with corrects the data_reg | |||||
 No.20651
pnp2084 Tester
Oct 21, 2022, 04:22
|
The attached fdc_fix.zip contains an example fix where the correct data_reg value is retrieved when sync is achieved. |
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No.20652
pnp2084 Tester
Oct 21, 2022, 04:37
|
I've created a pull request to make it easier to review the (sample) changes: https://github.com/mamedev/mame/pull/10454 |