prosolis
2f9f5cc995
Two sessions that were never separated in the working tree, so they land as one commit. check.sh ALL GREEN before and after both. SESSION 19 -- the ring rig gets a frame clock (FINDINGS 51). src/player/stream.s had no frame clock: it asked for record i the instant it finished i-1, outran any finite pipe, and never let the ring back up. The 49.1 sweep passing at 48 KB was therefore a wrap-correctness result and nothing else. PACE/PACEON ($18034/$18038) hold the decoder to 12 fps, so FR_HEAD-FR_TAIL finally means what it reads as: whole frames the decoder could still draw with delivery stopped dead. PACEON=0 free-runs and is what the wrap gate still uses, so every figure in 49 is unmoved. Paced, on the gate container: 64 KB holds 2 frames, 256 KB holds 7-8, 512 KB holds 14-15, all pixel-exact. Tolerance is ceiling-1, measured by cutting the pipe: 256 KB buys 500 ms of dead pipe, not 583. SLACK IS ACCUMULATED, NOT OWNED. It is built out of pipe-wire and a seek spends all of it. At 488 KB/s a 256 KB ring needs 4.83 s of play to reach its ceiling from empty; 512 KB needs 8.42 s to reach 14. A bigger ring raises the ceiling AND lengthens the climb, so a branch point does not ask "is the buffer big enough" but "has there been enough play since the last one" -- and Dragon's Lair's decision points are seconds apart. The rig now also says WHICH resource is binding: at 460 KB/s every ring from 192 KB to 512 KB is rate-bound at ceiling 4 and never fills, so larger rings are dead RAM in that scene. 20_seek_slack.py is the same model rewritten in Python from record sizes, sharing no code with the Lua producer: 35/35 ceilings inside its bracket. SESSION 20 -- the DMAC configuration was in the IPL ROM the whole time (FINDINGS 52). ROADMAP's "do this first" was to put the ADPCM stream on the bus. That needs a clocks-per-byte figure for the audio channel, and 11_cpu_budget.py was charging audio the DISK's rate -- 5 clk/B, its own help text calling it "single-address, bus held". Audio was being charged the favourable end of B3, a 242 KB/s open question. It never had to be a guess. The IPL ROM programs all four HD63450 channels itself and MAME boots the rig with it, so 21_iplrom_dmac.py reads the configuration out of the image and decodes the MC68450 fields. Eight (address, expected bytes, meaning) sites; a mismatch or an unknown revision exits non-zero. In check.sh, no emulator, milliseconds. ch3 DCR=$80, OCR=$32: dual address, 8-bit port, cycle steal WITHOUT hold, REQG=10 external request. The DMAC arbitrates once per byte with no burst to amortise the 5..8 + 2 over, so an audio byte is 16..19 clocks, not 5 -- the old debit was 3.2x..3.8x small. And on the bus it is still nothing: 651 B/frame is 1.25%..1.48% of a frame, about 4% of what the decoder leaves. P6's bus risk does not materialise. The unit worry was worth checking and nearly right: 15.6 kHz is 8 MHz/512 = 15,625 samples/s, two 4-bit samples to a byte = 7,812.5 B/s exactly, and AUDIO_KBPS=7.8 is that in decimal kB while the tool multiplied by 1024. THE DISK CHANNEL IS PROGRAMMED IDENTICALLY. ch1 (SASI) is DCR=$80 too, and so is ch0. That is 16..19 clocks per delivered byte, where 42.4 brackets W at 5..12 and 42.5 has W=8 already missing 47/120 frames. The only worked example of a disk DMA configuration on this machine sits above the entire bracket, and at that price nothing fits at any container size. It is not scsiexrom.bin so B3 stays open -- what changed is that a cheap configuration is now the thing that has to be SHOWN. W <= 12 is a requirement on the player's DMAC programming, not a range the hardware hands us, and it is now the largest open number in the project, ahead of the rate. An unforced cross-check fell out: 15_bus_occupancy.py's new W sweep puts W=8 at 105.7% of the frame, agreeing with 42.5's 47/120, from mode histograms and bus clocks respectively, two models sharing no code. Also: ADPCM outranks the disk at the arbiter (CPR 1 against 2), so an audio byte never waits and a video byte does -- relevant to 51's smooth-rate delivery model. README MEDIA. stream.lua gains DLX_SNAP_EVERY=1 (needs DLX_PACE, off by default, on no path check.sh takes) and tools/media/make_readme_media.py turns the PNGs into docs/img/. The stills and both clips are MAME's own screen pixels. Building it turned up something worth recording. 116 of 119 captured frames are pixel-exact against dlx.py; three are TORN -- frame n on top, frame n-1 below the tear line -- because MAME captured the screen while the block loop was partway down it. decode.s writes straight to the displayed page (one display path, 28.1), so a real player tears the same way, and this is the first time that consequence has been visible rather than argued. The script ASSERTS the tear and refuses to build otherwise, rather than trimming three frames and reporting "every frame I kept is exact". Second correction the capture forced: the snapshot fires before frame n is decoded, so the obvious reading is that it holds frame n-1 -- it does not, because MAME renders the screen at the end of the machine frame, by which time the 68000 has finished frame n. 11_cpu_budget.py's "validated to within 1 pt" line is also corrected: the model reads 2..10 pt HIGH and by more as the frame gets harder, which was already true before either session. src/player/decode.s is unchanged; decode.bin is still 1,296 B at the same MD5. Claude-Session: https://claude.ai/code/session_01194oWYW8DQXK1SZ2DnChW6
54 lines
2.4 KiB
Python
54 lines
2.4 KiB
Python
"""Load-time transforms every src/player/ front-end's loader has to do.
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Split out of prep_dlx.py in session 18 so that prep_dlx.py (the preloaded-stream
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rig) and prep_stream.py (the ring-buffer streaming rig, FINDINGS 49) share ONE
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copy of them. Two copies would drift, and the drift would be silent: both rigs
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would still decode, and only the colours or the codebook scaling would be
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subtly wrong in one of them.
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The split is a no-op by construction -- tools/bench/check.sh asserts prep_dlx.py
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still emits a byte-identical blob for the gate container.
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Neither transform is part of the per-frame cost being measured. The 68000 would
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do both once at load time; charging them to the inner loop would flatter or damn
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it for no reason.
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"""
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import numpy as np
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def expand_codebooks(d):
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"""CB1/CB4 to one WORD per pixel, so the inner loop movems them straight out.
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The high byte of every GVRAM word write is discarded by the hardware, so it
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is left zero and never has to be cleared. Word-per-pixel form is also what
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makes index scaling a shift rather than a multiply: lsl.w #5 and lsl.w #3.
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"""
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cb1 = np.zeros((d.k1, 16, 2), np.uint8); cb1[:, :, 1] = d.cb1.reshape(d.k1, 16)
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cb4 = np.zeros((d.k4, 4, 2), np.uint8); cb4[:, :, 1] = d.cb4.reshape(d.k4, 4)
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return cb1, cb4
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def pack_palette(d):
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"""24-bit palette -> GGGGGRRRRRBBBBBI, shared LSB chosen PER ENTRY.
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Choosing I per entry by minimum squared error rather than fixing it is worth
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1.96 dB (FINDINGS 23.3). Identical maths to tools/bench/verify_frame256.py,
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which is the point: the verifier and the loader must agree or a colour bug
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reads as a decoder bug.
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Returns (palette bytes 256x2 big-endian, index of the darkest entry). The
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encoder does not yet reserve a black entry (docs/STATUS.md, encoder gaps),
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so the letterbox gets the closest thing to black the palette has.
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"""
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pal = d.pal.astype(int)
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p6 = lambda v: ((v << 2) | (v >> 4)) & 0xFF
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f = pal >> 3
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render = lambda I: p6((f << 1) | I[:, None])
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I = (((render(np.ones(256, int)) - pal) ** 2).sum(1)
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< ((render(np.zeros(256, int)) - pal) ** 2).sum(1)).astype(int)
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words = (f[:, 1] << 11) | (f[:, 0] << 6) | (f[:, 2] << 1) | I
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palb = np.zeros((256, 2), np.uint8)
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palb[:, 0], palb[:, 1] = words >> 8, words & 0xFF
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dark = int(((render(I).astype(int)) ** 2).sum(1).argmin())
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return palb, dark, render(I)
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