Session 1: hardware research, content measurement, codec decision, MAME harness

Verified GVRAM is one word-access per pixel in ALL color modes; chose 256-color
256x192 with movem.l bursts (page 1 sacrificed as double-buffer).

Measured 8 scenes from the Blu-ray source: blit costs under 8% of the 12fps
cycle budget, so I/O is the bottleneck, not CPU. Naive delta+RLE reaches only
3.2:1 (365 KB/s, 470MB) -> decision to use 4x4 vector quantization (~30 KB/s).

"Shot on twos" assumption failed: the transfer has zero duplicate frames, so
12fps requires explicit decimation.

Documents three false measurement results and their root causes (per-frame
Floyd-Steinberg dithering, temporal denoise, exact-match dedupe on noisy source).

MAME Lua injection harness works and is reusable for cycle-cost measurement;
the IOCS _B_READ disk benchmark is blocked returning -1.

Claude-Session: https://claude.ai/code/session_01194oWYW8DQXK1SZ2DnChW6

This commit is contained in:

reala-misaki

2026-08-23 11:23:49 -07:00

commit 65112b9305

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										tools/bench/regs.lua
									
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				local cpu = manager.machine.devices[":maincpu"]

				local names={}

				for k,v in pairs(cpu.state) do names[#names+1]=tostring(k) end

				table.sort(names)

				print("[REGS] "..table.concat(names,", "))