dwt: visual injection experiments via the returning rdebug jump

dwt/visual/probe_hook.lua

@@ -0,0 +1,40 @@
+-- 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'