-- Interrupt diagnostic.  The stuck loop sits inside the LEVEL0 display-interrupt
-- test, which waits for the TMS34010's display interrupt.  MAME generates it when
-- VCOUNT == DPYINT and the display is enabled, provided INTENB has the DI bit.
--
-- Register map (MAME tms34010 enum, index*0x10 from 0xC0000000):
--   0x00 HESYNC 0x10 HEBLNK 0x20 HSBLNK 0x30 HTOTAL
--   0x40 VESYNC 0x50 VEBLNK 0x60 VSBLNK 0x70 VTOTAL
--   0x80 DPYCTL 0x90 DPYSTRT 0xA0 DPYINT 0xB0 CONTROL
--   0x110 INTENB 0x120 INTPEND 0x1B0 DPYTAP 0x1C0 HCOUNT 0x1D0 VCOUNT 0x1E0 DPYADR
--
--   INT_FRAMES=400 <mame> vt1200 ... -autoboot_script harness/mame/intr.lua

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

local maxframes = tonumber(os.getenv("INT_FRAMES") or "400")
local every     = tonumber(os.getenv("INT_EVERY") or "50")
local n = 0
local rd = function(a) return prog:read_u16(a) end

local seen = {}
local last_intenb, last_intpend = -1, -1
emu.register_frame_done(function()
	n = n + 1
	local intenb  = rd(0xc0000110)
	local intpend = rd(0xc0000120)
	local dpyctl  = rd(0xc0000080)
	seen[intenb] = (seen[intenb] or 0) + 1
	-- Report changes immediately; sampling every N frames can miss a transient.
	if intenb ~= last_intenb then
		print(string.format("f%4d INTENB CHANGED -> %04X (DI=%d)", n, intenb, (intenb & 0x0400) ~= 0 and 1 or 0))
		last_intenb = intenb
	end
	if intpend ~= last_intpend then
		print(string.format("f%4d INTPEND CHANGED -> %04X", n, intpend))
		last_intpend = intpend
	end
	if n % every == 0 then
		print(string.format(
			"f%4d DPYCTL=%04X INTENB=%04X(DI=%d) INTPEND=%04X DI=%d DPYINT=%04X VCOUNT=%04X VTOTAL=%04X HTOTAL=%04X HSBLNK=%04X",
			n, dpyctl, intenb, (intenb & 0x0400) ~= 0 and 1 or 0, intpend,
			(intpend & 0x0400) ~= 0 and 1 or 0, rd(0xc00000a0), rd(0xc00001d0),
			rd(0xc0000070), rd(0xc0000030), rd(0xc0000020)))
	end
	if n >= maxframes then
		print("distinct INTENB values seen:")
		for v, c in pairs(seen) do
			print(string.format("   INTENB=%04X  DI=%d  (%d frames)", v, (v & 0x0400) ~= 0 and 1 or 0, c))
		end
		machine:exit()
	end
end, "vt1200-intr")

dbg.execution_state = 'run'