pico-8 serialization / deserialization for bit-packing cartdata

serde.lua

function ser(n1,n2,n3,n4)
  return (n1&0xff)<<8 | n2&0xff |
    (n3&0xff)>>8 | (n4&0xff)>>16
end

function deser(n)
  return {
    (n>>8) & 0xff,
    n&0xff,
    (n<<8) & 0xff,
    (n<<16) & 0xff
  }
end

-- Usage:
-- cartdata(id)
-- local n = ser(0, 255, 128, 0)
-- dset(0, n)
-- local np = deser(dget(0))
-- print(np[2]) // 255
-- print(np[3]) // 128