-- see http://l...content-available-to-author-only...s.org/wiki/ReadWriteFormat

-- Write an integer in MSB order using width bytes.
function numbertobytes(num, width)
  local function _n2b(t, width, num, rem)
    if width == 0 then return table.concat(t) end
    table.insert(t, 1, string.char(rem * 0x100))
    return _n2b(t, width-1, math.modf(num/0x100))
  end
  return _n2b({}, width, math.modf(num/0x100))
end

io.write("<", numbertobytes(0x61626364, 4), ">\n")