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https://git.k-space.ee/arti/vt1200.git
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SDD
72a96862c7
Four-config A/B (IRQ wiring kept in all four; both mc68681 edits reverted in cfg 4): the console line and L3FA6E4B0's return are identical (HOST PORT - 15 / 6) in cfg 1-4. Verdict: PRE-EXISTING. Neither timing edit causes or relocates the failure. Methodology correction: hp_ret.lua's labels were on the wrong rets addresses. The real returns are L3FA6E4B0 -> 6, L3FA71BC0 -> 0x00900040, L3FA753D0 -> 0x00000408, L3FA767E0 -> 0. hp_ret2.lua fixes the addresses. What 6 is: not a device code. L3FA6E4B0 reduces five descriptor fields (struct+0x60/ 0x80/0xa0/0xc0/0xe0, written from the four sub-test calls) to a 5-bit value; 6 = 0b00110 = "L3FA71BC0 nonzero, L3FA753D0 nonzero". The caller turns any nonzero into 0x400, which the dispatcher maps to HOST PORT - 15. Flagged: L3FA753D0 returns 0x408 while all its own checks pass, so "nonzero" != "failed its checks"; polarity unresolved. Leads: COUNTER_READY is set by the firmware's own Start-Counter-Command read (reg 0x0E), is not in IMR, and is not handled by the ISR -- not the cause. The DUART clock (3.6864 MHz) could not be confirmed from the service guide. Variant MAME files kept in harness/mame/mame_edits/. Regression holds.
24 lines
915 B
Lua
24 lines
915 B
Lua
-- hp_ret2.lua -- return values, with the rets addresses verified from the disassembly:
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-- L3FA71BC0 rets @ 3FA753C0, L3FA753D0 (RXCHECK) @ 3FA767D0,
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-- L3FA767E0 (XMITPASS) @ 3FA77800.
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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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local function bp(addr, msg)
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dbg:command('bpset ' .. addr .. ',,{ printf "' .. msg ..
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' a8=%08X a7=%08X a9=%08X a11=%08X a13=%08X\\n", a8, a7, a9, a11, a13 ; g }')
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end
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bp("3fa753c0", "RET-BC0")
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bp("3fa767d0", "RET-RXCHECK")
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bp("3fa77800", "RET-XMITPASS")
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bp("3fa84fe0", "RET-L3FA6E4B0")
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bp("3fa6e4b0", "ENTER-GENERIC")
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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 >= tonumber(os.getenv("HP_FRAMES") or "700") then print("done "..n); machine:exit() end
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end, "vt1200-hp-ret2")
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dbg.visible_cpu = cpu
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dbg.execution_state = 'run'
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