Super Mario Land luascript

-- this outputs some information related to the map loading procedure when the screen scrolls,
-- hopefully helpful for researching and recreating the scroll bug
-- script by mugg ; with help from ais523, Sand

----- CONFIGURATION -----
local PRINT_INFO = true

local TRY_RUN_TESTS = true
local run_test =  -- only set one of these true
{
        [1] = false, -- unpause test
        [2] = true -- idle into B press/jumprun test
}
----- CONFIGURATION END -----

console.clear()
memory.usememorydomain("System Bus")

local cycles_at_frame_start = emu.totalexecutedcycles()
local cycles_at_frame_end = emu.totalexecutedcycles()
local print_after_this_frame = emu.framecount() + 1
local game_version = "-"
local t = ""
local t_frame_info = ""
local frames_processed = 0

-- these have to happen in the same frame
local requirement1 = false -- timer interrupt happens while ffea is 0x01
local requirement2 = false -- ffea gets set to 0x03

local bugframe_tbl = {}
local double_timer_interrupt_tbl = {}
local timer_interrupts_same_frame = 0

local waitframes = emu.framecount() +1 -- used by testing code, to bruteforce for the bug

if gameinfo.getromhash() == "3A4DDB39B234A67FFB361EE7ABC3D23E0A8B1C89" then
    game_version = "1.0"
elseif gameinfo.getromhash() == "418203621B887CAA090215D97E3F509B79AFFD3E" then
    game_version = "1.1"
else
    print("This script will work only with GB Super Mario Land v1.0 or v1.1.")
    return
end

function text(x, y, text, color, backcolor)
    gui.pixelText(x, y, text, color, backcolor)
end

event.onframestart(function()
    cycles_at_frame_start = emu.totalexecutedcycles()

    if emu.framecount() > print_after_this_frame then
        local prefix = ""
        if frames_processed > 1 then
            prefix = "\n"
        end
        t_frame_info = prefix .. "   FRAME " .. emu.framecount() + 1
    end
end)

event.onframeend(function()

    if emu.framecount()-1 > print_after_this_frame then
        t_frame_info = t_frame_info .. "  Cy:" .. emu.totalexecutedcycles() - cycles_at_frame_end
    end

    if emu.islagged()
    and emu.framecount()-1 > print_after_this_frame then
        t_frame_info = t_frame_info .. "  **LAG**"
    end

    cycles_at_frame_end = emu.totalexecutedcycles()

    -- only print if the string isn't empty
    if PRINT_INFO then
        if #t_frame_info > 0 and #t > 0 then
            print(t_frame_info .. "\n" .. t)
        elseif #t_frame_info > 0 then
            print(t_frame_info)
        end
    end

    -- bugframe happened, save framecount and pixel pos
    if requirement1 and requirement2 then
        print("Bug frame!!!")
        local bugframe_info = {emu.framecount(), memory.read_u8(0xFFE9)*8}
        table.insert(bugframe_tbl, bugframe_info)
    end

    -- reset values
    requirement1 = false
    requirement2 = false
    t = ""
    t_frame_info = ""
    timer_interrupts_same_frame = 0

    frames_processed = frames_processed + 1
end)

tastudio.onbranchload(function()
    print_after_this_frame = emu.framecount() + 1
    frames_processed = -1
    console.clear()
    bugframe_tbl = {}
    double_timer_interrupt_tbl = {}
end)

event.onloadstate(function()
    print_after_this_frame = emu.framecount() + 1
    frames_processed = -1
    console.clear()
    bugframe_tbl = {}
    double_timer_interrupt_tbl = {}
end)

-- Write to $FFEA
-- passed val is always 0, it seems, hinting that this hook is not fully implemented
event.on_bus_write(function(addr, val, flags)
    if emu.framecount() > print_after_this_frame then
        local raw_val = memory.read_u8(0xFFEA)
        local val = string.upper(string.format("%02x",raw_val))
        local myname = "Write $FFEA (" .. val .. ")"
        t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start

        if raw_val == 0x03 then
            requirement2 = true
        end
    end
end, 0xFFEA)

-- Write to $FFE9
event.on_bus_write(function(addr, val, flags)
    if emu.framecount() > print_after_this_frame then
        local val = string.upper(string.format("%02x",memory.read_u8(0xFFE9)))
        local myname = "Write $FFE9 (" .. val .. ")"
        t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
    end
end, 0xFFE9)

-- Exec $0040
event.on_bus_exec(function(addr, val, flags)
    if emu.framecount() > print_after_this_frame then
        local myname = "Execu $0040 (VBLANK INTERRUPT)"
        t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
    end
end, 0x0040)

-- Exec $0050
event.on_bus_exec(function(addr, val, flags)
    if emu.framecount() > print_after_this_frame then
        local myname = "Execu $0050 (TIMER INTERRUPT)"
        t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start

        local ffea = memory.read_u8(0xFFEA)
        if ffea == 0x01 then
            requirement1 = true
        end

        timer_interrupts_same_frame = timer_interrupts_same_frame + 1
        if timer_interrupts_same_frame >= 2 then
            --t = t .. "\nTwo Timer Interrupts!"
            table.insert(double_timer_interrupt_tbl, emu.framecount()+1)
        end
    end
end, 0x0050)

-- Exec $0060
--[[
event.on_bus_exec(function(addr, val, flags)
    if emu.framecount() > print_after_this_frame then
        local myname = "Execu $0060 (JOYPAD INTERRUPT)"
        t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
    end
end, 0x0060)
--]]

-- game version dependent execs
if game_version == "1.0" then

    event.on_bus_exec(function(addr, val, flags)
        if emu.framecount() > print_after_this_frame then
            local myname = "Execu $2258 (READ $FFEA)"
            t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
        end
    end, 0x224F)

    event.on_bus_exec(function(addr, val, flags)
        if emu.framecount() > print_after_this_frame then
            local myname = "Execu $2254 (READ $FFE9)"
            t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
        end
    end, 0x2254)

elseif game_version == "1.1" then

    event.on_bus_exec(function(addr, val, flags)
        if emu.framecount() > print_after_this_frame then
            local myname = "Execu $2258 (READ $FFEA)"
            t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
        end
    end, 0x2258)

    event.on_bus_exec(function(addr, val, flags)
        if emu.framecount() > print_after_this_frame then

            local myname = "Execu $225D (READ $FFE9)"
            t = t .. "\n" .. string.format("%-32s", myname) .. " cycle: " .. emu.totalexecutedcycles() - cycles_at_frame_start
        end
    end, 0x225D)

end

while true do

    gui.clearGraphics()

    if #bugframe_tbl > 0 then
        for i=1, #bugframe_tbl, 1 do
            local bugframe_entry = bugframe_tbl[i]

            if bugframe_entry ~= nil then

                local bugframe_framecount = bugframe_entry[1]
                local bugframe_pixel = bugframe_entry[2]
                local current_pixel = memory.read_u8(0xFFE9) * 8
                local display_pixel = (bugframe_pixel - current_pixel) - memory.read_u8(0xFF43)%8 + 216

                text(10, 10 + i*8, "bug Frame " .. bugframe_framecount, 0xFF00FF00, 0x80000000)

                if display_pixel > 160 then
                    text(136,10 + i*8, "--->", 0xFFFF0000, 0x80000000)
                else
                    gui.drawLine(display_pixel, 17, display_pixel, 144, 0xFFFF0000)
                end

                if display_pixel < 0 then
                    bugframe_tbl[i] = nil
                end

            end
        end
    end

    --[[
    if #double_timer_interrupt_tbl > 0 then
        for j=1, #double_timer_interrupt_tbl, 1 do
            local frame = double_timer_interrupt_tbl[j]
            text(10, 80 + j*8, "two timer interrupts frame " .. frame, 0xFF00FF00, 0x80000000)
        end
    end
    --]]

    if TRY_RUN_TESTS then

        if run_test[1] then
            -- Pause, then let this run while keeping previous input in taseditor
            -- script will attempt unpause at increasing framecounts
            tastudio.submitinputchange(emu.framecount(), "Right", true)
            tastudio.submitinputchange(emu.framecount(), "A", true)
            if emu.framecount() == waitframes then
                tastudio.submitinputchange(emu.framecount()+1, "Start", true)
            end
            if emu.framecount() > waitframes + 120 then
                savestate.loadslot(5)
                waitframes = waitframes + 1
            end
            tastudio.applyinputchanges()
        end

        if run_test[2] then
            -- Have Mario on the ground, clear upcoming 200 frames in taseditor
            -- script will attempt increasing amounts of idleframes then jumprun.
            if emu.framecount() >= waitframes then
                tastudio.submitinputchange(emu.framecount(), "Right", true)
                tastudio.submitinputchange(emu.framecount(), "B", true)
            end

            if emu.framecount() > waitframes+6 then
                tastudio.submitinputchange(emu.framecount(), "A", true)
            end

            if emu.framecount() > waitframes + 120 then
                savestate.loadslot(5)
                waitframes = waitframes + 1
            end
            tastudio.applyinputchanges()
        end

    end

    emu.frameadvance()
end