local a,sn,dp,rB=...
local function readBytes(off,count)
    return rB(dp,off,count):gsub("%\0","")
end

local FileTable = readBytes(2502,8)
if FileTable ~= "FILES   " then
    error("can't find filetable at offset 2502 " ..FileTable)
end
local function loadFileTable(offset)
    local fileTable = {}
    if not offset then
        offset = 2513
    end
    while true do
        local Filename = readBytes(offset,16)
        if Filename ~= "" then
            if Filename == "EOFTEOFTEOFTEOFT" then
                break
            end
            local file = {
                ["name"]=Filename,
                ["offset"]=tonumber(readBytes(offset+16,8),10),
                ["size"]=tonumber(readBytes(offset+24,2),10)
            }
            table.insert(fileTable, file)
        end
        offset = offset + 32
    end
    return fileTable
end
local fileTable = loadFileTable()

-- the first file should be the file SYSTEM.lua
local function findFile(filename)
    for i = 1, #fileTable do
        if fileTable[i]["name"] == filename then
            return i
        end
    end
    return nil
end

local fileIndex = findFile("SYSTEM.lua")
local Offset = fileTable[fileIndex]["offset"]
local Size = fileTable[fileIndex]["size"]
local FileHead = readBytes(Offset,9)

if FileHead ~= "STARTFILE" then
    error("filehead is not correct" .. FileHead)
end

local data = readBytes(Offset+9,Size*dp.getSectorSize()-9)
local systemData, err = load(data, "=SYSTEM.lua", "bt", _G)

if err then
    error(err)
end

if systemData == nil then
    error("systemData is nil!")
end

systemData(a,sn,dp,rB,readBytes,loadFileTable,findFile)

local ts=os.time()
while 1 do
    if os.time() - ts >= 0.5 then
        coroutine.yield()
    end
end