-- probe_hook.lua -- investigation only: log the DI hook stages of blinkpc.
-- Sets breakpoints at entry / ret_hook / the stock OS handler after the hook is
-- installed, prints PC/SP/ST, and resumes.  Never writes memory.
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 ARM = tonumber(os.getenv("HOOK_ARM") or "3450")
local STOP = tonumber(os.getenv("HOOK_STOP") or "3520")
local f = 0
local armed = false
local clock = os.getenv("FRAME_CLOCK")

local function bp(addr, tag)
	dbg:command(string.format(
		'bpset %s,,{ printf "HOOK %s pc=%%08X sp=%%08X st=%%08X a0=%%08X\\n", pc, sp, st, a0 ; g }',
		addr, tag))
end

emu.register_frame_done(function()
	f = f + 1
	if clock then
		local fh = io.open(clock, "w")
		if fh then fh:write(f .. "\n"); fh:close() end
	end
	if f == ARM and not armed then
		armed = true
		bp("1840190", "ENTRY")
		bp("18402d0", "RET")
		bp("3f7146d0", "OSH")
		print(string.format("probe_hook: armed at frame %d", f))
	end
	if f >= STOP then
		print("probe_hook: stopping")
		machine:exit()
	end
end, "vt1200-probe-hook")

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