-- code22_walk.lua
--
-- Breaks at the level-1 error dispatcher read (bit 0x3FDF0630) and dumps:
--   * registers sp / a13 / a14 / a8 / a9
--   * the word the dispatcher reads:  *a13(0xffe0)  = memory at (a13 - 0x20)
--   * a window of low RAM around the alleged slot a13-0x20
--   * the whole task stack, sp .. 0x5400, one line per word
--
-- All memory addresses in the debugger are BIT addresses; a word is 0x10
-- bits apart.  Only plain (unparenthesised) expressions are used: a
-- `d@(sp+20h)` action silently breaks bpset.
--
--   CW_FRAMES=300 <mame> vt1200 ... -debug -debugger none \
--       -autoboot_script harness/mame/code22_walk.lua

local machine = manager.machine
local cpu = machine.devices[':maincpu']
local dbg = machine.debugger
if not dbg then print("ERROR: no debugger"); machine:exit(); return end

local act = "{ "
	.. 'printf "DISP sp=%08X a13=%08X a14=%08X a8=%08X a9=%08X a11=%08X\\n", sp, a13, a14, a8, a9, a11 ; '
	.. 'printf "SLOT d@16E0=%04X d@16F0=%04X d@1700=%04X d@1710=%04X d@1720=%04X d@1730=%04X\\n", d@16E0, d@16F0, d@1700, d@1710, d@1720, d@1730 ; '
	.. 'printf "S00 %04X %04X %04X %04X %04X %04X %04X %04X\\n", d@5280, d@5290, d@52A0, d@52B0, d@52C0, d@52D0, d@52E0, d@52F0 ; '
	.. 'printf "S01 %04X %04X %04X %04X %04X %04X %04X %04X\\n", d@5300, d@5310, d@5320, d@5330, d@5340, d@5350, d@5360, d@5370 ; '
	.. 'printf "S02 %04X %04X %04X %04X %04X %04X %04X %04X\\n", d@5380, d@5390, d@53A0, d@53B0, d@53C0, d@53D0, d@53E0, d@53F0 ; '
	.. 'g }'

dbg:command("bpset 3fdf0630,," .. act)
print("breakpoint armed at 3fdf0630")

local maxframes = tonumber(os.getenv("CW_FRAMES") or "300")
local n = 0
emu.register_frame_done(function()
	n = n + 1
	if n >= maxframes then
		print("done (" .. n .. " frames)")
		machine:exit()
	end
end, "vt1200-cw")

dbg.visible_cpu = cpu
dbg.execution_state = 'run'