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SDD
5ef8712960
The dispatch status is 0x100 (printed as '22' in the message). A driver-side transparent low-RAM write log (VT1200_LOWLOG) shows the slot at bit 0x16F0 is written by the store at 3FDF9090 from a13(0x10), which L3FA7C050 sets to the literal 0x100 when the memory test L3F2018B0 returns non-zero. L3F2018B0 is the level-1 video-memory test (base bit 0x04000000, count 0x20000). Its failing checks: the 16-bit walking-bit read-back at 0x04000000 (baseline, unmapped) and, with video RAM mapped, the REFCNT (0xC00001F0) 'must change' check.
33 lines
1.1 KiB
Lua
33 lines
1.1 KiB
Lua
-- code22_probe.lua
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--
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-- Resolve two mechanics at the level-1 error dispatcher:
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-- (1) does a bpset fire BEFORE or AFTER its instruction executes?
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-- (2) what 32-bit value does the dispatcher read from *a13(0xffe0)?
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--
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-- We break at 0x3FDF0630 (the read) and at 0x3FDF0650 (the next instruction,
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-- jreq) and print a8 / a13 / the dword at the read address.
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--
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-- CP_FRAMES=300 <mame> vt1200 ... -autoboot_script harness/mame/code22_probe.lua
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local machine = manager.machine
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local cpu = machine.devices[':maincpu']
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local dbg = machine.debugger
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if not dbg then print("ERROR: no debugger"); machine:exit(); return end
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dbg:command('bpset 3fdf0630,,{ printf "AT-READ pc=%08X a13=%08X a14=%08X a8=%08X d@16F0=%08X\\n", pc, a13, a14, a8, d@16F0 ; g }')
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dbg:command('bpset 3fdf0650,,{ printf "AT-NEXT pc=%08X a8=%08X d@16F0=%08X\\n", pc, a8, d@16F0 ; g }')
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print("breakpoints armed")
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local maxframes = tonumber(os.getenv("CP_FRAMES") or "300")
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local n = 0
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emu.register_frame_done(function()
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n = n + 1
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if n >= maxframes then
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print("done (" .. n .. " frames)")
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machine:exit()
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end
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end, "vt1200-cp")
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dbg.visible_cpu = cpu
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dbg.execution_state = 'run'
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