Ded by 22

function AssembleASM(input,output)
    if(not fs.exists(input))then error("File doesnt exist: " .. input) end
    if(fs.exists(output))then error("File exists: " .. output) end
    local labels = {}
    local vars = {}
    local keyword_var = "define"
    local keyword_label = ":"
    local online = 1
    local codeline = 0
    local programstart = 600
    print("Reading file...")
    -- Safer to read file first, then compile as the fs hook is closed, and they is no risk of data loss.
    local source = fs.open(input,"r")
    local code = {}
    local line = source.readLine()
    while line do
      code[#code+1] = line
      line = source.readLine()
    end
    source.close()
    -- Compile Variables and labels, check for syntax errors
    print("Initializing...")
    for i = 1, #code do
        -- Handle variables
        if(#code[i]:gsub("%s+","") ~= 0)then
            codeline = codeline + 1
        end
        if(code[i]:find(keyword_var))then
             local val = str_shearWord(code[i],keyword_var)
             local nargs = {}
             -- Take spaces out of string, then split it into 2 variables
             val = val:gsub("%s+", "")
             -- Split string by $
             for word in string.gmatch(val, '([^$]+)') do
                table.insert(nargs, word)
             end
                if(#nargs > 2)then error("Syntax error line " .. online .. ": " .. code[i]) end
                -- Convert ASCII to hex
                if(tonumber(nargs[2]) == nil)then
                    nargs[2] = string.byte(nargs[2])
                end
               -- if(_G.ASM._HEXENCODE[string.upper(nargs[1])])then error("Syntax error line " .. online .. ": " .. code[i]) end
             vars[nargs[1]] = nargs[2]
            -- print(nargs[1] .. ": " .. vars[nargs[1]])
        end
        -- Handle labels
        if(code[i]:find(keyword_label))then
            local val = code[i]:gsub("%s+","")
            local nargs = {}
             for word in string.gmatch(val, '([^:]+)') do
                table.insert(nargs, word)
             end
             if(#nargs > 1 or nargs == nil)then
                 error("Syntax error line " .. online .. ": " .. code[i])
             end
             labels[nargs[1]] = codeline
             print(nargs[1] .. ": " .. labels[nargs[1]])
            -- print(nargs[1] .. ": " .. labels[nargs[1]])
        end
        online = online + 1
    end

    -- Get Bytes Per line
    codeline = 0
    online = 1
    linebytes = {}
    local code_backup = code -- LUA bug where this variable acts like a pointer and still writes to code, screw lua.
    print("Getting Bytes...")
    for i = 1, #code_backup do
        if(#code_backup[i]:gsub("%s+","") ~= 0 and not code_backup[i]:find(keyword_label) and not code_backup[i]:find(keyword_var))then
            local op  = string.upper(code_backup[i]:gsub("%s+",""):sub(1,3))
            local vtype = code_backup[i]:gsub("%s+",""):sub(4,4)
            local val = code_backup[i]:gsub("%s+",""):sub(4,#code_backup[i])
            if(val:sub(1,1) == "#")then val = val:sub(2,#val) end
            if(not _G.ASM._HEXENCODE[op])then error("Syntax error line " .. online .. ": " .. code_backup[i]) end
            if(vars[val] ~= nil)then
                if(_G.ASM._HEXENCODE[op]['REL'] ~= nil)then
                    error("Syntax error line " .. online .. ": " .. code_backup[i])
                end
                if(vtype == "#")then
                    code_backup[i] = op .. " #$" .. vars[val]
                else
                    if(not tonumber(vars[val]))then error("Syntax error line " .. online .. ": " .. code_backup[i]) end
                    code_backup[i] = op .. " $" .. vars[val]
                end
            elseif(labels[val] ~= nil)then
                if(_G.ASM._HEXENCODE[op]['REL'] ~= nil)then
                    code_backup[i] = op .. " *+" .. "00"
                else
                    local newBase = toHex(tonumber(programstart,16) + labels[val]-1)
                    if(#newBase < 4)then newBase = string.rep("0",4-#newBase) .. newBase end
                    code_backup[i] = op .. " $" .. newBase
                end
            end
            codeline = codeline + 1
            local op, otype, num = procInstructionType(code_backup[i],false,false)
            if(lineB == "op")then error("Syntax error line " .. online .. ": " .. code_backup[i]) end
            local lineB = getInstuctionBytes(op,otype)
            if(lineB == "err")then error("Syntax error line " .. online .. ": " .. code_backup[i]) end
            linebytes[#linebytes+1] = lineB
        end
        online = online + 1
    end
    -- Compile Code substitute variables and labels, check syntax
    -- Branch labels and jump labels, are controlled based on additions to the base program start
    codeline = 0
    online = 1
    local source = fs.open(input,"r")
    local code = {}
    local line = source.readLine()
    while line do
      code[#code+1] = line
      line = source.readLine()
    end
    source.close()
    local hexdump = ""
    print("Compiling code...")
    for i = 1, #code do
        if(#code[i]:gsub("%s+","") ~= 0 and not code[i]:find(keyword_label) and not code[i]:find(keyword_var))then
            -- Check if code references label or variable
            local op  = string.upper(code[i]:gsub("%s+",""):sub(1,3))
            local vtype = code[i]:gsub("%s+",""):sub(4,4)
            local val = code[i]:gsub("%s+",""):sub(4,#code[i])
            if(val:sub(1,1) == "#")then val = val:sub(2,#val) end

            if(not _G.ASM._HEXENCODE[op])then error("Syntax error line " .. online .. ": " .. code[i]) end

            if(vars[val] ~= nil)then
                if(_G.ASM._HEXENCODE[op]['REL'] ~= nil)then
                    -- No variable branching!
                    error("Syntax error line " .. online .. ": " .. code[i])
                end
                if(vtype == "#")then
                    code[i] = op .. " #$" .. vars[val]
                    --print(code[i])
                else
                    -- Direct index
                    if(not tonumber(vars[val]))then error("Syntax error line " .. online .. ": " .. code[i]) end
                    code[i] = op .. " $" .. vars[val]
                    --print(code[i])
                end
            elseif(labels[val] ~= nil)then
                -- Insert for relative branching
                local bytediff = 0
                if(_G.ASM._HEXENCODE[op]['REL'] ~= nil)then
                    -- Jump difference
                    local difference = labels[val] - (codeline+1)
                    if(difference < 0)then
                        local bytes = 1
                        for i = labels[val], codeline+1 do
                            bytes = bytes + linebytes[i]
                        end
                        bytediff = -bytes
                        print(bytes)
                        -- Subtract the amount of bytes taken by branch
                        bytediff = 256 + bytediff
                    else
                        for i = codeline+2, codeline+difference-1  do
                            bytediff = bytediff + linebytes[i]
                        end

                    end
                    bytediff = toHex(bytediff)
                    -- Insert branch difference into code
                    code[i] = op .. " *+" .. bytediff
                    --print(code[i])
                else
                    -- Insert for jumping
                    local newBase = toHex(tonumber(programstart,16) + labels[val]-1)
                    if(#newBase < 4)then newBase = string.rep("0",4-#newBase) .. newBase end
                    code[i] = op .. " $" .. newBase
                    --print(code[i])
                end
            end
            local hex = AssembleHEX(code[i],online)
            hexdump = hexdump .. hex
            codeline = codeline + 1
        end
        online = online + 1
    end
    -- Compile hex to bytes
    local hexbytes = ""
    local _hexdump = hexdump
    hexdump = hexdump:gsub("%s+","")
    if(#hexdump > 2)then
        for i=1, #hexdump, 2 do
            hexbytes = hexbytes .. string.char(tonumber(hexdump:sub(i,i+1),16))
        end
    else
        hexbytes[1] = string.char(tonumber(hexdump,16))
    end

    print("Hex Compiled: " .. _hexdump)
    --local f = fs.open(output,"w")
    --f.writeLine(":> HEX Source: " .. hexdump)
    --f.writeLine(hexbytes)
    --f.close()
    print("Hex outputed to: " .. output)
    print("Done. ")
end