RFC: Add 32bit x86-64 support to binutils

[H.J. Lu]

On Thu, Dec 30, 2010 at 11:40 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Dec 30, 2010 at 11:30 AM, Joseph S. Myers
> <joseph@codesourcery.com> wrote:
>> On Thu, 30 Dec 2010, H.J. Lu wrote:
>>
>>> On Thu, Dec 30, 2010 at 10:42 AM, Joseph S. Myers
>>> <joseph@codesourcery.com> wrote:
>>> > On Thu, 30 Dec 2010, H.J. Lu wrote:
>>> >
>>> >> Hi,
>>> >>
>>> >> This patch adds 32bit x86-64 support to binutils. Support in compiler,
>>> >> library and OS is required to use it.  It can be used to implement the
>>> >> new 32bit OS for x86-64.  Any comments?
>>> >
>>> > Do you have a public psABI document?  I think the psABI at the ELF level
>>> > needs to come before the binutils bits, at the function call level needs
>>> > to come before the GCC bits, etc.
>>>
>>> The psABI is the same as x86-64 psABI, except for 32bit ELF instead of
>>> 64bit.
>>
>> I don't think that's an adequate description.  If the "ILP32" name is
>> accurate then it's certainly wrong at the C level since some type sizes
>> are different, with effects in turn on such things as the description of
>> initial stack layout storing argv.  At the ELF level are you saying that
>> each relocation applies to a relocatable field of the same width as for
>> 64-bit (but with the width of the addend being restricted, of course)?  Do
>> any relocations applying to word64 fields need 32-bit variants applying to
>> word32 for the ILP32 ABI?
>
> ILP32 uses small model in x86-64 psABI.
>

Here is the ILP32 psABI:

http://www.kernel.org/pub/linux/devel/binutils/ilp32/


-- 
H.J.