Re: ARM SIM - add support to select SWI emulations to support.

[Nick Clifton <nickc@cambridge.redhat.com>]

Hi Richard,

> + extern unsigned int swi_mask;
> + 
> + #define SWI_MASK_DEMON	(1 << 0)
> + #define SWI_MASK_ANGEL	(1 << 1)
> + #define SWI_MASK_REDBOOT	(1 << 2)
> 
> Why make this a mask?  A major part of the problem here is that
> these SWI sets may be mutually incompatible.

Err really ?  I was under the impression that all three SWI protocols
used completely different number sets and so could be supported
simultaneously.  It certainly looks that way in the ARMul_OSHandleSWI
function.

> Why not just require the user to  select the right one?

The user may need to support more than one protocol and the
user/script setting this option might not know which protocol is going
to be used by a given binary.  For example the current newlib
implementation defaults to using ANGEL, but the libgloss
implementation uses REDBOOT.

Besides there are enough free bits that there is no reason not to be
flexible and provide the ability to support more than one protocol at
the same time.

Cheers
        Nick