-- m3-check.lua -- load the M3 COFF with dwt/loader/loader.lua, read the
-- compiled branch/Xlib marker words, and prove a window was mapped by reading
-- the white background pixel in VRAM.
--
-- M3_LOADER_LUA   path to vendor/vt1200/dwt/loader/loader.lua
-- LOADER_END      loader inspection/exit frame
--
-- The marker read runs one frame before loader.lua's inspection/exit frame.
-- XSync is diagnostic only; the pass requires the visible white pixel.
--
-- The DWT root window is a fine monochrome weave, so one set bit at (150,150)
-- cannot distinguish the mapped client window from the root.  Require the
-- whole 32-bit VRAM word containing (150,150) to be 0xFFFFFFFF, and check a
-- second interior word at (250,200) so the client area is proven solid, not
-- just a lucky white stripe.

dofile(os.getenv("M3_LOADER_LUA"))

local ENDF = tonumber(os.getenv("LOADER_END") or "3400")

-- Window: XCreateSimpleWindow(display, root, 100, 100, 400, 200, 2, 0, 1).
-- The client area starts at (102,102); sample well inside it.
local VRAM_BASE = 0x04000000
local VRAM_PITCH = 2048		-- VR319: 2048 bits per row
local WHITE_WORD = 0xFFFFFFFF
local PX, PY = 150, 150
local PX2, PY2 = 250, 200

local frames = 0
local checked = false

local function vram_word(prog, x, y)
	local bit = VRAM_BASE + y * VRAM_PITCH + x
	local word = bit - (bit % 32)
	return prog:read_u32(word), word, bit
end

emu.register_frame_done(function()
	frames = frames + 1
	if frames == ENDF - 1 and not checked then
		checked = true
		local prog = manager.machine.devices[':maincpu'].spaces['program']
		local display = prog:read_u32(0x018A8000)
		local root = prog:read_u32(0x018A8020)
		local window = prog:read_u32(0x018A8040)
		local sync = prog:read_u32(0x018A8060)
		local sum = prog:read_u32(0x018A8080)
		local maxv = prog:read_u32(0x018A80A0)
		local ltv = prog:read_u32(0x018A80C0)
		local screens = prog:read_u32(0x018A80E0)
		local rootoff = prog:read_u32(0x018A8100)

		-- The full words containing each sample pixel.
		local pix, word, bit = vram_word(prog, PX, PY)
		local pix2, word2, bit2 = vram_word(prog, PX2, PY2)
		local solid = pix == WHITE_WORD
		local solid2 = pix2 == WHITE_WORD

		print(string.format(
			"M3: display=%u root=%u window=%u sync=%d sum=%d max=%d lt=%d screens=0x%x root_off=0x%x",
			display, root, window, sync, sum, maxv, ltv, screens, rootoff))
		print(string.format(
			"M3: pixel(%d,%d) bit=0x%08X word=0x%08X value=0x%08X %s",
			PX, PY, bit, word, pix, solid and "SOLID-WHITE" or "not-solid-white"))
		print(string.format(
			"M3: pixel(%d,%d) bit=0x%08X word=0x%08X value=0x%08X %s",
			PX2, PY2, bit2, word2, pix2, solid2 and "SOLID-WHITE" or "not-solid-white"))

		local ok = display ~= 0 and root ~= 0 and window ~= 0
			and sum == 55 and maxv == 22 and ltv == 1
			and screens == 0x480 and rootoff == 0x40
			and solid and solid2
		if ok then
			print("M3 MAME: PASS")
		else
			print("M3 MAME: FAIL")
		end
	end
end, "m3-check")