-- probe_irq.lua -- which periodic interrupt can a payload hook?
--
-- Boot the OS (VT1200_SKIP_LEVEL1=1), then count entries to the handlers that
-- the firmware's RAM trampolines point at.  The trampolines are the 6-byte
-- `JA target` stubs at the low-RAM vector page (see dwt/notes/VISUAL_INJECTION.md).
--
-- Investigation only: this script uses breakpoints to count.  The resident-hook
-- acceptance run does not.
--
--   VT1200_SKIP_LEVEL1=1 <mame> vt1200 ... -autoboot_script dwt/visual/probe_irq.lua

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

local START = tonumber(os.getenv("IRQ_START") or "3200")
local STOP  = tonumber(os.getenv("IRQ_STOP") or "3500")
local EVERY = tonumber(os.getenv("IRQ_EVERY") or "50")

local hits = { di = 0, int1 = 0, int2 = 0 }
local function bp(addr, key)
	dbg:command(string.format(
		'bpset %s,,{ %s = %s + 1 ; g }', addr, key, key))
end
bp("3f7146d0", "hits.di")
bp("3f7144c0", "hits.int1")
bp("3f714530", "hits.int2")

local rd = function(a) return prog:read_u16(a) end
local f = 0
local armed = false
local last = { di = 0, int1 = 0, int2 = 0 }

emu.register_frame_done(function()
	f = f + 1
	if f == START then
		armed = true
		print(string.format("probe_irq: armed at frame %d (DI handler 3F7146D0, INT1 3F7144C0, INT2 3F714530)", f))
	end
	if armed and (f % EVERY == 0) then
		print(string.format(
			"f%4d DI=%d(+%d) INT1=%d(+%d) INT2=%d(+%d) DPYCTL=%04X DPYINT=%04X INTENB=%04X INTPEND=%04X VCOUNT=%04X",
			f, hits.di, hits.di - last.di, hits.int1, hits.int1 - last.int1,
			hits.int2, hits.int2 - last.int2,
			rd(0xc0000080), rd(0xc00000a0), rd(0xc0000110), rd(0xc0000120), rd(0xc00001d0)))
		last.di, last.int1, last.int2 = hits.di, hits.int1, hits.int2
	end
	if f >= STOP then
		print(string.format("probe_irq: totals DI=%d INT1=%d INT2=%d over %d frames",
			hits.di, hits.int1, hits.int2, STOP - START))
		machine:exit()
	end
end, "vt1200-probe-irq")

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