Thomas Harte
7d7aa2f5d5
Eliminates repetition of the unpacking of register 3 into a horizontal sync count.
2017-08-26 14:37:03 -04:00
Thomas Harte
28550c0227
Breaks the 6845 bus cycle into a phase 1 and a phase 2 per the belief that sync line changes, which are observable, happen at the end of the first phase rather than at the beginning of the next. This may have interrupt timing effects, as machines often derive an interrupt from sync.
2017-08-26 13:56:23 -04:00
Thomas Harte
6e99169348
Permits the 6845's bus state to be examined by an owner, eliminating the need to buffer it in the bus handler. But more than that it allows the CRTC to decide when it adjusts the various outputs respective to the main phase. So a net effect of the change is that the CPC now sees vsync a cycle earlier, because my current reading of the 6845 datasheet is that it is set at the end of phase 1, not the beginning of the next phase 1.
2017-08-26 12:59:59 -04:00
Thomas Harte
3caa4705ca
Limits sync counter size.
2017-08-26 12:31:19 -04:00
Thomas Harte
039aed1bd1
Switches the two sync counters to upward-going rather than downward, as a more likely match to the way the rest of the 6845 implementation.
2017-08-25 21:26:01 -04:00
Thomas Harte
a914eadc85
Ensured that register 6 is checked on every loop.
2017-08-22 22:17:45 -04:00
Thomas Harte
e956740c56
Refactors the 6845 more clearly to break out the acts of ending a line and ending a frame, changing the way the memory address is altered — the end-of-line value is provisionally stored and then used if necessary — in order to do so.
2017-08-22 21:54:48 -04:00
Thomas Harte
e88a51e75e
Worked logic all the way down to the CPC. If the 8272 announces that it is asleep, it is now no longer clocked. Also very slightly cut down on IRQ line chatter to the Z80.
2017-08-20 12:05:00 -04:00
Thomas Harte
2d9efccc98
Introduced a master 'is sleeping' flag. I'm starting to think there's a pattern forming here.
2017-08-20 10:43:53 -04:00
Thomas Harte
8ce46b6e49
Having spotted that I was using my single-character loop counter names incorrectly (quelle surprise!), got a bit more explicit. Also flattened into a single loop so that I can break rather than returning.
2017-08-20 10:32:09 -04:00
Thomas Harte
669e0caff5
Ensured the head_unload_delay values are properly seeded, and generalised the quick escape.
2017-08-19 22:06:56 -04:00
Thomas Harte
e208f03636
Corrects the US colour palette, effectively undoing what was a mistaken adjustment for the time when Oric-centric phase alignment was built into the CRT based on a false calculation that it wouldn't affect the machines that generate chrominance functionally.
2017-08-16 09:58:34 -04:00
Thomas Harte
cc9d23f23b
Inverted meaning of register_masks, as it's a bit weird that the mask is inverted immediately upon usage. It's a left-over from thinking the unused bits should be 1s; unit tests reveal they should be 0s. Comment updated appropriately.
2017-08-16 09:29:48 -04:00
Thomas Harte
1a831bcf9b
Quick fix: supply the port being written to correctly.
2017-08-16 09:15:57 -04:00
Thomas Harte
82367a2246
Added documentation.
2017-08-16 09:14:56 -04:00
Thomas Harte
3947347d88
Introduces active input handling for the AY and uses it in the CPC to give proper, active keyboard input, rather than push-on-select, which was only ever a temporary hack. Also maps a few more keys for the Amstrad.
2017-08-15 22:47:17 -04:00
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
55055c7847
Minor: ensured immediate line comparison works. But I think my problem might be trying to do this as straight line logic?
2017-08-14 19:08:20 -04:00
Thomas Harte
cddcd0fb79
Put my money where my mouth is and switched the superclass of WD1770 to MFMController, eliminating duplicated (/factored out) code.
2017-08-14 16:32:53 -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
a10389a22c
Factored out the stuff of stuffing the bus.
2017-08-14 12:42:22 -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
