Pico8 number-to-hex function

to_hex.p8

hex_abc = '0123456789abcdef'
function to_hex(num)
  local str = ''
  for i=0,7 do --8 packs of 4 bits for 32 bit number
    local digit = num

    local shift = (i - 4)*4
    if shift < 0 then digit = shl(digit, -shift)
    else digit = shr(digit, shift) end

    digit = band(digit, 0xf) --cut away any bits outside what we're looking at (especially important for repeated sign bit from right shift at i=7)

    str = sub(hex_abc, digit+1, digit+1) .. str
  end
  return str
end