CydandClaude Opus 4.8
47fe174c6e
The VDB is the ISA card that fans the PC's Cirrus Logic framebuffer to the six secondary cockpit displays (5 mono + 1 color), dividing the pixel clock. From the driver (CODE/RP/MUNGA_L4/L4SVGA16.ASM, L4VB16.CPP; "Adam's port decoder design" -- Adam G., VWE hardware): 0x300/0x308/0x310 three VGA-DAC-style palette groups 0x31A / 0x319 splitter high-color clock divider ON / OFF New emulated VDB device in vpxlog.cpp at I/O 0x300-0x31A (active when logging, disable with VDB=0): decodes palette write-address/data/mask/read-address and the clock strobes, recording palette contents + splitter state so the six- display encoding can be decoded later. Validated: with gauges enabled (gauge.conf, setenv arg4=g) the game issues "splitter clock ON (0x31A)" -> captured. The board is write-only (game never reads it, per driver + owner), so its absence is not the crash. Crash diagnosis (BTL4OPT.EXE CODE+0x123B): the faulting routine is a heap free() with boundary-tag coalescing; it was handed a garbage block pointer (value 2). Symptom of upstream corruption, reached only when the RIO is in sync and the sim advances. HISTORY.md gains a "Cockpit display hardware -- the VDB" section with the attribution. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
27 lines
459 B
Plaintext
27 lines
459 B
Plaintext
[sdl]
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output=opengl
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[dosbox]
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memsize=32
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machine=svga_s3
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[cpu]
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core=dynamic
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cputype=pentium
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cycles=max
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[serial]
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serial1=disabled
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serial2=disabled
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[autoexec]
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mount c "C:\VWE\TeslaRel410\ALPHA_1"
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c:
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cd \REL410\BT
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set VIDEOFORMAT=svga
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set BLASTER=A220 I5 D1 H5 P330 T6
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set TEMP=c:\
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rem arg4=g enables the gauge/secondary displays -> exercises the VDB splitter
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call setenv.bat r s n g
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32rtm.exe -x
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btl4opt.exe -egg test.egg
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32rtm.exe -u
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echo ALPHA1-RUN-DONE
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pause
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