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

H.J. Lu
2012-06-26T19:48:06Z

On Tue, Jun 26, 2012 at 12:36 PM, Mark Butler <butlerm@middle.net> wrote:
> On Monday, May 14, 2012 11:31:11 AM UTC-6, H.J. wrote:
>>
>> Support for the x32 psABI:
>>
>> http://sites.google.com/site/x32abi/
>>
>> is added in Linux kernel 3.4-rc1.  X32 uses the ILP32 model for x86-64
>> instruction set with size of long and pointers == 4 bytes.  X32 is
>> already supported in GCC 4.7.0 and binutils 2.22...Here is a
>> patch to extend x86-64 psABI for x32.  Any comments?
>>
>
> May I ask why the decision was made to use ILP32 instead of L64P32?   The
> latter would seem to avoid lots of porting problems in particular.  And if
> porting difficulties are the major complained about x32, is it really too
> late to switch?  Thanks - mdb

x32 is designed to replace ia32 where long is 32-bit, not x86-64.

--
H.J.