Thomas Harte
aefbafa18d
Centralised the 8272's actions of setting the non-DMA execution flag, picking the drive and head and loading the head for accessing commands, and switched error flag if read ID doesn't find anything.
2017-08-15 21:49:10 -04:00
Thomas Harte
d12c834f9c
Increased amount reported.
2017-08-15 20:35:33 -04:00
Thomas Harte
56de5cb2b3
Removed one further logging event.
2017-08-15 20:18:32 -04:00
Thomas Harte
709257a0c5
Quick fix: also treat reception of sync as a reason not to stop looking for a data address mark.
2017-08-15 20:16:56 -04:00
Thomas Harte
75a9d2bb33
Started withdrawing logging, reduced index hole count back to the correct number and tried to increase read_data rigour.
2017-08-15 20:12:01 -04:00
Thomas Harte
73080d6c36
Added an easy way for disk controllers to clamp termination of written data exactly to the index hole.
...
This commit also temporarily provides a whole load of extra logging and minor logic improvements from the 8272. I'm mid-flow on finding a particularly vicious error in its handling of writing; wait for the pull request. But, at least: now waits for the first part of a post-ID gap before writing data, and attempts partially to handle appearance of the index hole during writing a track. More work to do on that though.
2017-08-15 16:05:10 -04:00
Thomas Harte
9d77f33611
Dealt with another source of repeating magic constants: the command numbers.
2017-08-15 11:06:10 -04:00
Thomas Harte
7d132f81f7
Increased logging by quite a distance and made an attempt once again to allow the processor some time to supply the first byte when writing before declaring overrun.
2017-08-15 10:50:28 -04:00
Thomas Harte
6553bf05b4
Corrected multi-sector reads: ensured the incremented sector number isn't replaced by the original, and that the controller returns to scanning mode.
2017-08-14 22:27:31 -04:00
Thomas Harte
0816d3f5a9
Corrected 'read deleted data' command. It's 0xc, not 0xb.
2017-08-14 21:41:20 -04:00
Thomas Harte
a366298022
Factored out the standard [M]FM gap and mark groups, to increase 8272 readability and because it's pretty-much certain I'll need them again if ever I try to tackle e.g. the 8271.
2017-08-14 16:03:35 -04:00
Thomas Harte
4df9307d25
Factored out the dull and repetitious stuff of writing n bytes of the same value.
2017-08-14 15:50:36 -04:00
Thomas Harte
9038ba622e
Added a quick version of read track.
2017-08-14 14:34:56 -04:00
Thomas Harte
7b8bb0297a
Implemented single density version of format track.
2017-08-14 13:03:17 -04:00
Thomas Harte
0da02d3902
Added read/write escape clauses if faced with a read-only disk.
2017-08-14 12:53:18 -04:00
Thomas Harte
2e5ad19fe1
Minor tidying.
2017-08-14 12:42:48 -04:00
Thomas Harte
cefec7a19f
Sought more robustly (i.e. less repetitively) to handle dispatch, including cancelling seeks where appropriate.
2017-08-14 10:37:39 -04:00
Thomas Harte
7264fbb3d2
read_id now clears status. I probably need to find a way to generalise this.
2017-08-14 09:58:55 -04:00
Thomas Harte
8a7b23dc9e
Ensured data-accessing commands cancel seeks on their drives. Also introduced a count of drives currently seeking in order to make for a slightly better broad-phase test in run_for.
2017-08-14 09:45:39 -04:00
Thomas Harte
b7065575f3
Added (empty) call-ins for DMA usage; switched to having the 'is seeking' bit in the status register stay high until sense interrupt status, but now it goes high even for seeks that don't actually go anywhere, and corrected interpretation of the specify command, with a positive result: the received step rate time, now that it's being interpreted correctly, is much shorter.
2017-08-14 09:04:22 -04:00
Thomas Harte
7ea703f150
Started making provisions for a DMA-compatible implementation. Re: the CPC, it sounds like DMA acknowledge might be permanently wired, causing DMA mode seemingly to work from the 8272's point of view.
2017-08-14 08:38:00 -04:00
Thomas Harte
1011143dbe
Sought to correct my interpretation of 'gap 3'.
2017-08-13 21:52:48 -04:00
Thomas Harte
9ace6e1f71
Applied minimum constraints for specified parameters.
2017-08-13 19:25:57 -04:00
Thomas Harte
5221837be8
Fixed Non-DMA flag for the format track execution phase. The emulated machine now provides sector details.
2017-08-13 18:51:06 -04:00
Thomas Harte
e1e9a06712
Made an attempt at format a track.
2017-08-13 18:05:19 -04:00
Thomas Harte
b0a7208cc7
Strung together a very basic version of 8272 write [/deleted] data. Lots of cases as-yet unhandled.
2017-08-13 12:50:07 -04:00
Thomas Harte
eec42aa7ae
Entrusted further status to drives; also adjusted them to report read only if diskless, which I now believe to be correct.
2017-08-13 11:50:49 -04:00
Thomas Harte
5f42022c1d
Added a tester for the control mark.
2017-08-12 17:35:14 -04:00
Thomas Harte
11d0c37506
Attempted to find a more expressive way for maintaining state — macros for all conditions, to bind both values and destinations.
2017-08-12 17:33:52 -04:00
Thomas Harte
27d1dc5c37
Removed some old printfs.
2017-08-12 16:49:20 -04:00
Thomas Harte
7135259cc1
Sought to flesh out error conditions.
2017-08-12 16:36:37 -04:00
Thomas Harte
4909325e79
Implemented read deleted data.
2017-08-12 13:01:17 -04:00
Thomas Harte
a4ee697ed1
Quickie: head unload is scheduled only if the head is presently loaded.
2017-08-12 12:53:45 -04:00
Thomas Harte
0f15a2f97f
Relented: it actually looks like status bytes aren't per-drive. But each drive may fail at seeking individually. So that piece of state accumulates at the 8272 drive.
2017-08-12 12:52:36 -04:00
Thomas Harte
89ace671a4
Corrected unload time. Was 8000 times too short.
2017-08-12 09:44:01 -04:00
Thomas Harte
e7db2a2f6d
Sought to introduce head loading and unloading delays.
2017-08-12 09:36:21 -04:00
Thomas Harte
ffb1a14ace
Minor: clear status registers before a read data.
2017-08-11 18:56:33 -04:00
Thomas Harte
2eed24e859
Made an initial attempt at [a subset of] multi-sector reads.
2017-08-10 11:11:26 -04:00
Thomas Harte
b11d142cff
Switched to descriptive names.
2017-08-08 20:35:41 -04:00
Thomas Harte
021ff8674e
Added something for sense drive status.
2017-08-08 20:30:54 -04:00
Thomas Harte
47732ffb98
Prevented the 8272 from overreading ID fields (and, by doing so, overrunning its internal buffer). Exposed the MFMController's CRC generator for inspection.
2017-08-07 12:37:22 -04:00
Thomas Harte
d07f3216ab
Added a broad phase on whether seeking is ongoing.
2017-08-07 12:12:59 -04:00
Thomas Harte
68c73184b1
Had failed to spot that by taking control of stepping at this level, the appropriate invalidate_tracks were not being sent.
2017-08-07 10:36:53 -04:00
Thomas Harte
7f824d6494
Ensured seeks and recalibrates end immediately if no seeking is required.
2017-08-07 10:31:32 -04:00
Thomas Harte
3219212f03
A closer inspection of the data sheet seems to suggest that invalid command sequences will post ST0.
2017-08-07 07:35:41 -04:00
Thomas Harte
d90e35e5bd
Added a bunch of comments, and ensured that the data request bit remains set for the entire period that command bytes are accepted.
2017-08-07 07:27:00 -04:00
Thomas Harte
73f8488150
Reaching the end of the usable part of my day, decided to tidy up a little before bed with indentation that reflects a distinction between top-level entry points and mere loops.
2017-08-06 22:14:18 -04:00
Thomas Harte
3853966a1e
Removed formal storage of ST3, as it just seems to be composed live. This may turn out also to be the best way to deal with ST0–2, time will tell. Also took a stab at the error in responding properly to the ROM's intended use of seek might be accepting new commands as replacements for old ones rather than rejecting them. That didn't seem to do the trick.
2017-08-06 22:10:12 -04:00
Thomas Harte
d63893a437
Collapsed implementations of recalibrate and seek, and decided to intend to go for an upward count on steps taken rather than a downward one. But seek continues presently to fail.
2017-08-06 21:52:52 -04:00
Thomas Harte
90c74043f5
Remembered to toggle off RQM between bytes. CAT now works.
2017-08-06 21:21:59 -04:00
