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Re: x32 psABI draft version 0.2
On Wed, Feb 16, 2011 at 12:39 PM, Andrew Pinski <pinskia@gmail.com> wrote:
> On Wed, Feb 16, 2011 at 12:35 PM, Chris Metcalf <cmetcalf@tilera.com> wrote:
>> For what it's worth, the Tilera 64-bit architecture (forthcoming) includes
>> support for a 32-bit compatibility layer that is similar to x32. ?It uses
>> 64-bit registers throughout (e.g. for double and long long), but 32-bit
>> addresses. ?The addresses between 2GB and 4GB are not directly usable as
>> 64-bit addresses since we sign-extend all 32-bit values to make the ISA
>> more straightforward. ?We use the "compat" layer to provide our syscall
>> table, since we don't have a traditional compatibility layer in this mode
>> (unlike x86_64 and i386).
>
> This sounds more like MIPS' n32 than x32 really.
>
Yes, x32 can access the full 4GB address space. There are some
additional optimizations which can be done in x32, but not in x86-64
small model.
--
H.J.