Hello,

The attached patch replaces the function register_buffer(regnum) with 
regcache_collect(regnum, buffer).

regcache_collect() is the counter-part to supply_register().  It 
extracts a single raw register from the register cache as part of 
processing a target_store_registers() request.  Unlike register_buffer() 
this interface doesn't make assumptions about the underlying register cache.

Targets that are directly manipulating the registers[] and 
register_valid[] arrays should consider themselves as being ``on notice''.

Potential follow-ons to this patch are: add a ``struct regcache'' 
parameter; and add ``struct regcache'' to ``struct thread_info''; and 
parameterise target_{fetch,store}_registers() with ``struct regcache'' 
or ``struct thread_info''.

Testing continues...

Eli, note the tweek to go32-nat.c.

thoughts?
Andrew