-- Is the TMS34010 display controller enabled, and what does the firmware have
-- in the display registers?  The video renderer (and therefore the driver's
-- scanline/frame dump) only runs when DPYCTL bit 15 is set.
--
--   DPY_FRAMES=600 <mame> vt1200 ... -autoboot_script harness/mame/dpyctl.lua

local machine = manager.machine
local cpu = machine.devices[':maincpu']
local dbg = machine.debugger
local prog = cpu.spaces['program']

local maxframes = tonumber(os.getenv("DPY_FRAMES") or "600")
local every     = tonumber(os.getenv("DPY_EVERY") or "50")
local n = 0
local seen_enabled = false

local function rd(a) return prog:read_u16(a) end

emu.register_frame_done(function()
	n = n + 1
	local dpyctl = rd(0xc0000080)
	if (dpyctl & 0x8000) ~= 0 then seen_enabled = true end
	if n % every == 0 then
		print(string.format(
			"frame %5d DPYCTL=%04X%s CONTROL=%04X DPYSTRT=%04X DPYINT=%04X DPYTAP=%04X DPYADR=%04X",
			n, dpyctl, (dpyctl & 0x8000) ~= 0 and " <ENABLED>" or "",
			rd(0xc00000b0), rd(0xc0000090), rd(0xc00000a0), rd(0xc00001b0), rd(0xc00001e0)))
	end
	if n >= maxframes then
		print("display enabled at any point: " .. tostring(seen_enabled))
		machine:exit()
	end
end, "vt1200-dpyctl")

dbg.execution_state = 'run'