reala-misaki
65112b9305
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
37 lines
1.1 KiB
ArmAsm
37 lines
1.1 KiB
ArmAsm
FLAG = $18000
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STAT = $18004
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NREAD = $18008
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BUF = $20000
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CHUNK = 65536 ; bytes per read
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RECS = CHUNK/256 ; 256-byte records per read
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NCHUNK = 16 ; 16 x 64KB = 1MB total
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org $10000
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start:
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move.l #1,FLAG.l ; signal: started
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move.l #NCHUNK,d6
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moveq #0,d5 ; record position
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moveq #0,d4 ; completed count
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loop:
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movem.l d4-d6,-(sp)
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moveq #$46,d0 ; _B_READ
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move.l #$80000000,d1 ; PDA=$80 (SASI unit0), mode=0
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move.l d5,d2 ; position (records)
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move.l #CHUNK,d3 ; byte count
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lea BUF,a1
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trap #15
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movem.l (sp)+,d4-d6
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move.l d0,STAT.l ; last status
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tst.l d0
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bmi.s failed
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addq.l #1,d4
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move.l d4,NREAD.l
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add.l #RECS,d5
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subq.l #1,d6
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bne.s loop
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move.l #$FF,FLAG.l ; signal: done OK
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stop: bra.s stop
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failed:
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move.l #$EE,FLAG.l ; signal: error
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bra.s stop
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