8-bit processors back-end optimizations

[Steinar Bang]

>>>>> Jim Wilson <wilson@cygnus.com>:

> The main problem with 8 bit targets is the lack of registers.  If
> you don't have 8 registers or so, then you won't be able to get gcc
> working without resorting to tricks.  The 6811 port for instance
> pretended that it had registers in zero page memory.  This gave
> inefficient code in some cases, but it apparently did work.

Using the zero page was the common way of making up for missing
registers on the 6502 processor, and if I remember correctly it was a
close relative architecture wise, of the 6802.