Re: Creating X32 ABI code with GCC?

[Jonathan Wakely <jwakely.gcc@xxxxxxxxx>]

On 21 May 2012 18:55, Vincent Diepeveen wrote:
> hi,
>
> Kernel 3.4 supports X32 ABI.
>
> see
> http://kernelnewbies.org/Linux_3.4#head-039c9d273884c9639937c10d68b4a3214869eb4b
>
> This could give fantastic speedups at x64 hardware as it combines the
> advantages of 64 bits
>  programming, bunch of registers, with the advantage of still reusing the
> old codes 'signed integer' lookup
> which right now slows down so much in x64 as it creates an extra sign
> extension for the lookup 32 bits signed
>  value to 64 bits signed value.
>
> Does GCC already support this and if so which options can i trigger this
> with GCC?
>
> If so does this work at all x64 processors as well?
>
> If i google i see a few postings about X32 'backported to GCC' attempt in
> 2011 somewhere, but no confirmation whatsoever.

Google harder :)

If I search for x32 gc the top hit is the x32 project homepage which says

"X32 is functional complete with C, C++, Objective C and Fortran on
GCC trunk as of revision 177914"

The manual for GCC 4.7 documents the -mx32 switch at
http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/i386-and-x86_002d64-Options.html