Commit Graph

6 Commits

Author SHA1 Message Date
kris
ab4b4f22fd Refactor opcode schedulers and implement one based on the ortools TSP
solver to minimize the cycle cost to visit all changes in our estimated
list.

This is fortunately a tractable (though slow) computation that does give
improvements on the previous heuristic at the level of ~6% better
throughput.

This opcode schedule prefers to group by page and vary over content, so
implement a fast heuristic that does that.  This scheduler is within 2%
of the TSP solution.
2019-01-02 23:10:03 +00:00
kris
a8688a6a7e Memoize hamming_weight to optimize runtime 2019-01-02 22:25:16 +00:00
kris
6de5f1797d Reimplement opcode scheduler to one that is ~as fast as before. As a
bonus we now maintain much better tracking of our target frame rate.

Maintain a running estimate of the opcode scheduling overhead, i.e.
how many opcodes we end up scheduling for each content byte written.

Use this to select an estimated number of screen changes to fill the
cycle budget, ordered by hamming weight of the delta.  Group these
by content byte and then page as before.
2019-01-02 22:16:54 +00:00
kris
8e3f8c9f6d Implement a measure of similarity for two bool arrays and use it to measure
how close we are getting to encoding the target image.
2019-01-02 00:24:25 +00:00
kris
7c5e64fb6f Optimize for cycles/pixel by weighting each output byte by the hamming
weight of the xor of old and new frames, and switch to setting the
new byte directly instead of xor'ing, to improve efficiency of decoder.

Instead of iterating in a fixed order by target byte then page, at
each step compute the next change to make that would maximize
cycles/pixel, including switching page and/or content byte.

This is unfortunately much slower to encode currently but can hopefully
be optimized sufficiently.
2019-01-02 00:03:21 +00:00
kris
0b78e2323a Initial working version of image encoder. This tries to optimize the
bytestream by prioritizing bytes to be XOR'ed that have the highest
hamming weight, i.e. will result in the largest number of pixel
transitions on the screen.

Not especially optimized yet (either runtime, or byte stream)
2019-01-01 21:50:01 +00:00