My thinking here is that for really simple processors there'll be 256 or less, meaning that they can be stored by simple uint8_t; for every other processor I can currently think of it'll likely be uint16_t.
Either way, that's a much better outcome than using plain pointers, which on architectures I currently build for will always be 8 bytes. For the simple processors I can get eight times as much into the cache; for the others four times.