Thomas Harte
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b7065575f3
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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.
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2017-08-14 09:04:22 -04:00 |
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Thomas Harte
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7ea703f150
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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.
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2017-08-14 08:38:00 -04:00 |
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Thomas Harte
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1011143dbe
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Sought to correct my interpretation of 'gap 3'.
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2017-08-13 21:52:48 -04:00 |
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Thomas Harte
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9ace6e1f71
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Applied minimum constraints for specified parameters.
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2017-08-13 19:25:57 -04:00 |
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Thomas Harte
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5221837be8
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Fixed Non-DMA flag for the format track execution phase. The emulated machine now provides sector details.
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2017-08-13 18:51:06 -04:00 |
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Thomas Harte
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e1e9a06712
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Made an attempt at format a track.
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2017-08-13 18:05:19 -04:00 |
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Thomas Harte
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b0a7208cc7
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Strung together a very basic version of 8272 write [/deleted] data. Lots of cases as-yet unhandled.
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2017-08-13 12:50:07 -04:00 |
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Thomas Harte
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eec42aa7ae
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Entrusted further status to drives; also adjusted them to report read only if diskless, which I now believe to be correct.
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2017-08-13 11:50:49 -04:00 |
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Thomas Harte
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5f42022c1d
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Added a tester for the control mark.
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2017-08-12 17:35:14 -04:00 |
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Thomas Harte
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11d0c37506
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Attempted to find a more expressive way for maintaining state — macros for all conditions, to bind both values and destinations.
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2017-08-12 17:33:52 -04:00 |
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Thomas Harte
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27d1dc5c37
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Removed some old printfs.
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2017-08-12 16:49:20 -04:00 |
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Thomas Harte
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7135259cc1
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Sought to flesh out error conditions.
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2017-08-12 16:36:37 -04:00 |
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Thomas Harte
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4909325e79
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Implemented read deleted data.
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2017-08-12 13:01:17 -04:00 |
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Thomas Harte
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a4ee697ed1
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Quickie: head unload is scheduled only if the head is presently loaded.
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2017-08-12 12:53:45 -04:00 |
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Thomas Harte
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0f15a2f97f
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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.
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2017-08-12 12:52:36 -04:00 |
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Thomas Harte
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89ace671a4
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Corrected unload time. Was 8000 times too short.
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2017-08-12 09:44:01 -04:00 |
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Thomas Harte
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e7db2a2f6d
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Sought to introduce head loading and unloading delays.
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2017-08-12 09:36:21 -04:00 |
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Thomas Harte
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ffb1a14ace
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Minor: clear status registers before a read data.
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2017-08-11 18:56:33 -04:00 |
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Thomas Harte
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e4f04d0977
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Merge branch 'master' into AYFidelity
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2017-08-11 14:41:08 -04:00 |
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Thomas Harte
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a5593bec79
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Threw in support for the light-pen trigger.
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2017-08-10 15:00:14 -04:00 |
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Thomas Harte
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a1e2646301
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Imposed counter size limits.
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2017-08-10 14:58:24 -04:00 |
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Thomas Harte
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6a6e5ae79c
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Forced users of the 6845 to be explicit about which type. So far with no effect.
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2017-08-10 12:28:57 -04:00 |
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Thomas Harte
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02d792c003
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Simplified logic slightly, avoiding repetition.
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2017-08-10 11:48:37 -04:00 |
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Thomas Harte
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be8e7a4144
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Eliminated false register aliasing, restricted register sizes and locked out reading and writing where appropriate.
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2017-08-10 11:22:30 -04:00 |
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Thomas Harte
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b1dbd7833a
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Merge branch 'master' into 6845Address
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2017-08-10 11:15:08 -04:00 |
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Thomas Harte
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a4c910f1de
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This appears to be a more accurate take on 6845 address advancement — it is necessary that character output has finished for the line address to be updated.
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2017-08-10 11:12:53 -04:00 |
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Thomas Harte
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2eed24e859
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Made an initial attempt at [a subset of] multi-sector reads.
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2017-08-10 11:11:26 -04:00 |
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Thomas Harte
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b11d142cff
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Switched to descriptive names.
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2017-08-08 20:35:41 -04:00 |
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Thomas Harte
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021ff8674e
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Added something for sense drive status.
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2017-08-08 20:30:54 -04:00 |
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Thomas Harte
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e3d1f4fe1e
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Subjectively, this might be more correct. It definitely prevents intermediate frequencies. More research required.
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2017-08-08 17:58:35 -04:00 |
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Thomas Harte
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3bdedfd749
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Improved comments.
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2017-08-08 07:44:46 -04:00 |
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Thomas Harte
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46278ff297
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Experimental: is this meant to be a compare-before-increment?
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2017-08-07 23:02:29 -04:00 |
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Thomas Harte
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390ecec3d9
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Added: now declines to pass on output if in input mode for ports A and B.
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2017-08-07 19:56:22 -04:00 |
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Thomas Harte
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41a30c147d
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Adjusted: invalid register selection simply deselects all registers.
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2017-08-07 19:51:36 -04:00 |
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Thomas Harte
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4709ae80cb
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Added port direction tests.
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2017-08-07 19:36:55 -04:00 |
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Thomas Harte
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7fbb455836
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Per the CPC test I'm checking, 0s should be returned for non-retained bits, not 1s.
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2017-08-07 19:07:12 -04:00 |
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Thomas Harte
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745afd217f
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The port input/output flags are now honoured; reading a port that is set as an output returns the current output value.
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2017-08-07 19:01:18 -04:00 |
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Thomas Harte
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47732ffb98
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Prevented the 8272 from overreading ID fields (and, by doing so, overrunning its internal buffer). Exposed the MFMController's CRC generator for inspection.
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2017-08-07 12:37:22 -04:00 |
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Thomas Harte
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d07f3216ab
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Added a broad phase on whether seeking is ongoing.
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2017-08-07 12:12:59 -04:00 |
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Thomas Harte
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68c73184b1
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Had failed to spot that by taking control of stepping at this level, the appropriate invalidate_tracks were not being sent.
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2017-08-07 10:36:53 -04:00 |
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Thomas Harte
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7f824d6494
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Ensured seeks and recalibrates end immediately if no seeking is required.
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2017-08-07 10:31:32 -04:00 |
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Thomas Harte
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3219212f03
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A closer inspection of the data sheet seems to suggest that invalid command sequences will post ST0.
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2017-08-07 07:35:41 -04:00 |
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Thomas Harte
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d90e35e5bd
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Added a bunch of comments, and ensured that the data request bit remains set for the entire period that command bytes are accepted.
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2017-08-07 07:27:00 -04:00 |
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Thomas Harte
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73f8488150
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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.
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2017-08-06 22:14:18 -04:00 |
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Thomas Harte
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3853966a1e
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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.
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2017-08-06 22:10:12 -04:00 |
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Thomas Harte
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d63893a437
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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.
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2017-08-06 21:52:52 -04:00 |
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Thomas Harte
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90c74043f5
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Remembered to toggle off RQM between bytes. CAT now works.
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2017-08-06 21:21:59 -04:00 |
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Thomas Harte
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600445d90a
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Made a first attempt to return sector contents.
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2017-08-06 20:40:29 -04:00 |
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Thomas Harte
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e4b405fd3d
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With the ROM now using a read ID to set its expectations, implemented that and fixed FIND/READ_HEADER macros for multiple use. Execution now reaches the unimplemented section of read data.
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2017-08-06 20:32:46 -04:00 |
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Thomas Harte
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3b7ecbdf0d
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Renamed result_ to result_stack_ to emphasis the fact that it goes backwards. Switched meaning of CB so that it is set for the entire command, execution and result phases.
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2017-08-06 20:17:12 -04:00 |
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