CORE_ADDR representation

[Stan Shebs]

Daniel Jacobowitz wrote:
> This comes up again and again, and has at least three times in the
> past month with Jan's PIE patches.  Is it time for us to have opaque
> arithmetic on target addresses?
>   
Urgh.  On the plus side, the months of busywork lets us avoid dealing 
with the brain-strainingly hard problems. :-)
> This truncates the high bits.  MIPS sign-extends pointers, even
> internally in CORE_ADDR, and this results in separate debug info files
> for MIPS executables being relocated off to la-la land.
Heh, I remember getting hosed that way by a MIPS in 1994...

> For instance, should we always internally sign-extend CORE_ADDR?
> Always internally zero-extend?  Having it vary by target has been a
> recurring problem.
>   
I would say to declare that CORE_ADDR is fundamentally 0..memtop, so it 
should be unsigned and zero-extend.

Can unsigned->signed->diddle->unsigned be encapsulated for MIPS only?

Stan