Thomas Harte
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76a64d13a0
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Made a first attempt at ZX81 emulation.
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2017-06-13 21:25:55 -04:00 |
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Thomas Harte
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1e975859c2
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Started splitting ZX80 and ZX81 paths. Also the '80 fires its horizontal sync a little earlier than the '81, so pulled that back a little.
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2017-06-13 20:09:09 -04:00 |
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Thomas Harte
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4c5261bfa0
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Made first attempt to use the horizontal counter for something; here for sync timing only, even though I've gone exclusively with '81-style timing for now.
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2017-06-12 22:28:30 -04:00 |
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Thomas Harte
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8b09b4180b
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This now at least remembers whether it is meant to be a ZX81 and has storage for a horizontal counter.
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2017-06-12 21:33:16 -04:00 |
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Thomas Harte
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b9dbb6bcf8
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Discovered my timing error: the I/R <-> A loads should take an extra cycle. This means the ZX80 now finally takes the correct 207 cycles per line. Fixed the video output wave to be clocked at the appropriate rate.
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2017-06-12 18:55:04 -04:00 |
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Thomas Harte
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302c2e94de
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Corrected lingering hard-coded mask. So titles for memory configurations above 1kb now load.
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2017-06-11 21:27:46 -04:00 |
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Thomas Harte
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06fe07932a
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While tidying up, killed an unused instance variable.
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2017-06-11 21:21:26 -04:00 |
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Thomas Harte
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6913c7a018
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This also can just use rom_mask_.
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2017-06-11 19:29:20 -04:00 |
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Thomas Harte
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6b602c74b7
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Made an attempt to support memory maps other than the unexpanded default of 1kb.
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2017-06-11 19:29:02 -04:00 |
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Thomas Harte
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e40d553045
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Bumped the tape parser up into the machine to ensure a maintained state. Temporarily disabled normally-timed tape playback.
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2017-06-11 18:31:43 -04:00 |
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Thomas Harte
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e5b30cdfbb
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Attempted to ensure appropriate resumption of processing after quick-reading a tape byte.
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2017-06-11 17:28:47 -04:00 |
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Thomas Harte
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ba5f34f827
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Narrowed view to the centre 80% of a frame.
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2017-06-11 17:24:32 -04:00 |
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Thomas Harte
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84d2feb2e6
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Cleaned up and implemented fast-tape hack. I've decided it'd be better to test some other software, potentially to give multiple issues to think about, rather than sitting around with just the one.
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2017-06-11 16:42:49 -04:00 |
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Thomas Harte
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d910a4fd38
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Adjusted to signal an interrupt during the refresh cycle rather than weirdly just afterwards. Which cuts video timing down by 4 cycles a line. There still might be a problem here somewhere though, as I'm getting 206 cycles/line and the internet states it should be 207.
Also: lots of printfs have grown temporarily as I try to figure out what I'm doing so wrong as to break loading.
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2017-06-11 13:32:20 -04:00 |
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Thomas Harte
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5626d35bc4
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Tried flipping the bit meaning; decided at least to leave it in full-byte form.
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2017-06-06 18:38:05 -04:00 |
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Thomas Harte
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63e0802f4e
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Ensured tape input appears on the returned value.
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2017-06-06 18:16:27 -04:00 |
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Thomas Harte
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e3ee9604a5
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Added comments.
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2017-06-06 18:01:33 -04:00 |
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Thomas Harte
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8c66e1d99d
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Factored out ZX80/81 video and rejigged to ensure it will keep ticking over irrespective of whether the machine is supplying data.
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2017-06-06 17:53:23 -04:00 |
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Thomas Harte
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ca9e8aecd6
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Made a seemingly unsuccessful attempt to add tape input.
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2017-06-06 10:13:32 -04:00 |
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Thomas Harte
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cc4cb45e9d
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Implemented keyboard input and ensured that the signal generated is marked as composite, putting the colour-suppression ball into the CRT's court.
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2017-06-06 09:25:18 -04:00 |
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Thomas Harte
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ebbf6e6133
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Surprisingly, I think this may actually be the correct output: stopped throwing away the I part of the refresh register and flipped black and white.
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2017-06-06 09:03:09 -04:00 |
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Thomas Harte
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cba07dec7e
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Doubled up to display all eight pixels. To confirm that they are the wrong pixels.
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2017-06-06 08:59:00 -04:00 |
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Thomas Harte
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6f7037b2b1
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Made an initial stab at outputting half the correct pixels.
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2017-06-06 08:55:07 -04:00 |
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Thomas Harte
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ef4b2f963d
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Probably more-or-less corrected. But this is all a bit too interdependent.
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2017-06-05 23:52:56 -04:00 |
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Thomas Harte
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97f3ff03b6
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Restored white background and attempted to correct output timing deficiencies. Incomplete success.
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2017-06-05 23:50:04 -04:00 |
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Thomas Harte
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2fbc7a2869
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Made a very basic attempt at getting something that at least demarcates proper graphics output.
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2017-06-05 23:32:49 -04:00 |
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Thomas Harte
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4983718df7
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Got to outputting something to the CRT. Should be just proper syncs and a paper background. It's not synchronising properly, so something is amiss in my timing.
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2017-06-05 10:47:42 -04:00 |
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Thomas Harte
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23ca00fd9a
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Added memory fuzzing as a way to verify state being written by the Z80. Eventually discovered the HALT problem as fixed in the last commit, so have stripped away the caveman stuff again.
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2017-06-05 10:36:07 -04:00 |
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Thomas Harte
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893f61b490
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Attempted specifically to reproduce the 1kb ZX80 memory map in the hope of getting compact lines and in case mirroring is why I'm getting completely empty video reads. Still no action.
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2017-06-05 09:38:49 -04:00 |
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Thomas Harte
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7e3a46c33e
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[Re]discovered that sync may also be a product of the interrupt cycle. So started looking into that.
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2017-06-04 21:54:55 -04:00 |
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Thomas Harte
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73654d51dd
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Wired up actually to run.
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2017-06-04 18:37:13 -04:00 |
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Thomas Harte
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096551ab3e
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Made a first attempt to hash out the ZX80's bus. Video output isn't yet going though. Can't seem to find clarity on whether horizontal sync is really programmatic. Let's see.
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2017-06-04 18:32:23 -04:00 |
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Thomas Harte
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c485c460f7
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Imported the ZX80 and 81 system ROMs (though not publicly), added enough code to post their contents into C++ world.
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2017-06-04 18:08:35 -04:00 |
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Thomas Harte
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d2637123c4
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Added necessary support to get as far as an empty window when attempting to load a piece of ZX80 software.
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2017-06-04 17:55:19 -04:00 |
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