the Archimedes 2000 compiler lets
you do bank-switching for code, but
not for RAM, i think.

it also lets you specify the
absolute addresses used for the
code or idata or xdata segments
specified by individual object
modules; this is specified with
linker directives.

maybe your compiler has the same.

you could do the switching with
macros, as needed

#define switchto(A) ... (depends on you)

code, code, code
patch, patch, patch...
switchto(0)
code, code, code

or, for individual accesses,
#define banked_uchar(BANK,ADDR)
(switchto(BANK),
xdata *) (ADDR)))
might work.

james