ARM and virtual/raw registers

[Andrew Cagney]

> In addition to the above, we also have the case of the CPSR register.  On 
> old ARM chips (or on non-thumb chips up to armv4), this register is, or 
> can be mimicked as being, part of the PC.  This suggests to me that the 
> current decoding shenanigans that are currently hidden in some of the 
> back-end code should probably be moved into the virtual-raw conversion 
> layer.  That is, register_convirt_{to,from}_virtual(CPSR) (or whatever 
> it's really called) should be responsible for the updating of raw-PC or 
> raw-CPSR as appropriate.

Hmm, what exactly do you mean by mimicked?  Can the entire register 
contents be constructed from information found in the other raw/hardware 
registers?  If that is the case then making it a pseudo-register and 
using register_{read,write} should do the trick.

(notice - convert-to-virtual free zone).

enjoy,
Andrew