In looking at the RS08 configuration registers, you can't help but notice that they _could_ have been much more tightly packed. For example: the ICSC1 and ICSC2 registers occupy 16 bits of RAM address space at $0014 and $0015 -- but only 5 of these sixteen bits are actually used. Similarly, locations $0017 and $0018 could clearly be combined into a single byte -- with two bits to spare.
Does anyone know why Freescale chose to abandon so many bit addresses in low RAM, rather than implementing them and allowing their use as flags? I would think that the real estate savings from not doing this would be marginal.