Re: RFA/ARM: Switch mode when setting PC

[Andrew Cagney <cagney@gnu.org>]

> This patch fixes several failures in virtfunc.exp for arm-sim/-mthumb.  The
> problem is that the non-virtual thunk for pDe->vg() is emitted in ARM mode
> and called via _call_via_r2.  But the rest of the program is Thumb mode, and
> nothing tells the simulator (or target; I haven't tested this on hardware
> yet but I expect the same result) to switch to ARM.  So it gets very
> confused.
> 
> This is somewhat suboptimal in that if you want, for some reason, to call
> something marked as an ARM function with Thumb mode enabled you will have to
> set $ps yourself _after_ setting $pc.  I think it's still a good idea,
> though.  OK?

(sorry, but I don't understand that paragraph - doesn't that code set 
the $ps after setting the $pc?)

The ari contains this yellow card:

write pc
Replace write_pc() with get_frame_base_address or get_frame_id; at 
present the inferior function call code still uses this when doing a 
DECR_PC_AFTER_BREAK

the concern is with the way write_pc is being called to perform two 
different operations:

- decrement the pc just after the target stops
Arrrg!
- jump to a specific address
As with an inferior function call or jump.

I think it would be better to have two methods so that it's clear that 
this case only applies when doing a jump.

Andrew