[x86-64 psABI] RFC: Extend x86-64 psABI to support x32

[H. Peter Anvin]

On 06/28/2012 02:03 PM, Mark Butler wrote:
> On Tuesday, June 26, 2012 1:53:01 PM UTC-6, H. Peter Anvin wrote:
>
>     It's worth noting that there are *no* Linux platforms that are not
>     ILP32
>     or LP64, so adding a third memory model is likely to cause even more
>     problems...
>
>
> Care to comment on what sort of things would be likely to cause a large
> number of problems porting to an L64P32 model?  I understand that L32P64
> (as in Windows 64 bit) causes lots of problems, because there is a lot
> of code that assumes that a pointer can be converted to a long and back.
>   That would not be a problem with L64P32 however, because there
> pointers would be smaller than longs rather than larger.

Every time you introduce a new model you will have problems, but in 
Linux it is a strong assumption that sizeof(long) == sizeof(void *).

	-hpa


-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.