-- When the CPU is parked in the POST delay loop, dump the stack so we can see
-- the caller chain -- i.e. who passes the absurd delay count, and where the
-- count comes from.
--
--   <mame> vt1200 -rompath harness/mame/roms -video none -sound none -nothrottle \
--       -debug -debugger none -autoboot_script harness/mame/stackwalk.lua -autoboot_delay 0
--
-- TMS34010 note: SP is a *bit* address, and a 32-bit word occupies 32 bit
-- addresses, so consecutive stack words are +/- 32.

local function hex(v) return string.format("%08X", v) end

local machine = manager.machine
local cpu = machine.devices[':maincpu']
local dbg = machine.debugger
local prog = cpu.spaces['program']
local pc = cpu.state['PC']
local sp = cpu.state['SP']

if not prog or not prog.read_u32 then
	print("ERROR: program space has no read_u32")
end

local TARGET = tonumber(os.getenv("WALK_PC") or "0x3FDCE400")
local SKIP = tonumber(os.getenv("WALK_SKIP") or "40")
local frames = 0
local done = false

emu.register_frame_done(function()
	frames = frames + 1
	if done then return end
	if pc.value == TARGET and frames > SKIP then
		done = true
		local s = sp.value
		print(string.format("=== parked at %s  SP=%s  frame=%d ===", hex(TARGET), hex(s), frames))
		for i = -4, 28 do
			local a = (s + i * 32) & 0xFFFFFFFF
			local v = prog:read_u32(a)
			local tag = ""
			if v >= 0x3F200000 and v < 0x40000000 then
				tag = string.format("   <- ROM bit addr -> file 0x%06X", (v - 0x3F200000) / 8)
			elseif v < 0x00200000 then
				tag = "   <- low RAM bit addr"
			end
			print(string.format("  [%+3d] @%s = %s%s", i, hex(a), hex(v), tag))
		end
		machine:exit()
	end
end, "vt1200-stackwalk")

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