Thomas Harte
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cddcd0fb79
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Put my money where my mouth is and switched the superclass of WD1770 to MFMController , eliminating duplicated (/factored out) code.
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2017-08-14 16:32:53 -04:00 |
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Thomas Harte
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8a7b23dc9e
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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.
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2017-08-14 09:45:39 -04:00 |
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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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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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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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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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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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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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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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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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Thomas Harte
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01efb645cb
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Took a reasonable gamble that the CHRN reported is from internal registers, not from the last-found header.
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2017-08-06 19:57:34 -04:00 |
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Thomas Harte
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e9972aa0dd
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Added respect for the index-hole limit on reading, and an error phase.
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2017-08-06 19:25:44 -04:00 |
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Thomas Harte
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1c9a744b01
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Made an effort to start inspecting ID fields, at least. Discovered that my emulation has somehow stopped proceeding beyond sense interrupt status though. Fix one in that area: adjust ST0 just in time for the sense interrupt status response, as that'll need to specify the drive number properly.
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2017-08-06 18:06:20 -04:00 |
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Thomas Harte
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6c5b562d97
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Made an attempt at some of the correct seek/recalibrate behaviour: it's now asynchronous from command processing and able to work on up to four drives at once. I just probably am not yet hitting all the status flags I need to hit.
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2017-08-06 15:22:07 -04:00 |
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Thomas Harte
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a7103f9333
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Disks are now communicated to the 8272. Which is able to handle four of them.
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2017-08-06 13:24:14 -04:00 |
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Thomas Harte
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c12425e141
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Added storage for the extended four status registers, and made an attempt at implementing the two most trivial result-phase commands. Am slightly paused momentarily trying to figure out whether seek activity is orthogonal to read/write activity.
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2017-08-06 12:55:57 -04:00 |
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Thomas Harte
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89f6de1383
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Started on a real ugly-implementation coroutine approach, and implemented specify as a fairly trivial first command: it has no result phase, and is the only thing called by AMSDOS as part of the initialisation sequence.
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2017-08-06 12:36:18 -04:00 |
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Thomas Harte
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29288b690e
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Switched disk controllers to be instantiated explicitly in terms of cycles, created an Amstrad-specific subclass of the 8272 to record the direct programmatic availability of all disk motors bundled together, and otherwise adjusted to ensure the thing is clocked and that the motor is enabled and disabled appropriately. The 8272 is also now formally a subclass of the incoming MDM controller.
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2017-08-06 09:45:16 -04:00 |
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Thomas Harte
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25fd3f7e50
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Mildly increased work in here, still primarily oriented towards logging what I actually need to get done.
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2017-08-05 22:26:59 -04:00 |
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Thomas Harte
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3e984e75b6
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Strung up an empty shell that eventually should contain the 8272, and added appropriate IO decoding to the Amstrad.
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2017-08-05 19:45:52 -04:00 |
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