Re: X32 psABI status update
From: H.J. Lu
Date: Thu Mar 17 2011 - 01:21:25 EST
On Wed, Mar 16, 2011 at 7:57 PM, Mike Frysinger <vapier@xxxxxxxxxx> wrote:
> On Wednesday, March 16, 2011 08:39:57 H.J. Lu wrote:
>> On Tue, Mar 15, 2011 at 10:24 PM, Mike Frysinger wrote:
>> > so we get back to my original e-mail:
>> > are you getting a unique host tuple for this ? or are you
>> > extending x86_64-linux-gnu ? so the only way of knowing which ABI is to
>> > check for the output of the compiler+compiler flags ?
>> As I said, the target is x86_64- linux-gnu and you just add -mx32 to
>> CFLAGS. The x86_64- linux-gnu binutils and GCC support x32.
> ok, took long enough, but that answers most things. your usage of "x32-"
> prefixed binaries in the documentation seems to imply a lot more than the fact
> you just picked those locally to avoid system collisions. this isnt a wiki
> page, otherwise i'd clean things up for you.
Any suggestion how to create a wiki page for x32?
> in looking at the gcc files, it doesnt seem like there's any defines setup to
> declare x32 directly. instead, you'd have to do something like:
> #ifdef __x86_64__
> # if __SIZEOF_LONG__ == 8
> /* x86_64 */
> # else
> /* x32 */
> # endif
> any plans on adding an __x32__ (or whatever) cpp symbol to keep people from
> coming up with their own special/broken crap ? or are there some already that
> i'm not seeing ?
The idea is in most cases, you only need to check __x86_64__ since x32 and
x86-64 are very close. In some cases, x32 is very different from x86_64, like
assembly codes on long and pointer, you can check __x86_64__ and __LP64__.
In glibc, I used a different approach by using macros REG_RAX, .., MOV_LP,
ADD_LP, SUB_LP and CMP_LP in assembly codes.
I added a simple howto for x32 compiling to
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