Re: [Libjit-developers] libjit and AMD64

[Gopal V]

Basile STARYNKEVITCH wrote:

> I thought that some work has already started on AMD64, but the only file 
> I can find (related to AMD64) in the latest CVS of libjit is 
> libjit/jit/jit-apply-x86-64.h

That is nearly the first step which needs work. Basically, getting
the interpreter working on amd64 involves fixing the amd64 jit apply,
so that functions can be called (somewhat like what libffi or ffcall
does).

Is quite painful to debug and get it "right". The code generator and
instruction selection is slightly easier from that point onwards.

> It is quite strange that the only way of generating machine code on 
> AMD64 seems to be LLVM http://llvm.org/ apparently the GNU lightning 
> 1.2b port is not fully complete....

Actually, pnet CVM's (i.e old engine) has a fair bit of x86_64 native
code generation.

http://cvs.sv.gnu.org/viewvc/dotgnu-pnet/pnet/engine/md_amd64.h?revision=1.5&view=markup

http://t3.dotgnu.info/blog/hacks/ecx-vs-rcx-2005-11-13-14-45.html

Is just that real life has caught up to me really badly over the last
year, for me to jump into jit land.

> This seems quite strange, since I thought that AMD64 (or x86-64) is the 
> dominant architecture (at least on servers) today...

The focus was to get the x86 libjit ready for the Trumpf folks to
deploy. And we actually managed to get the x86 JIT to perform pretty
decently, eventhough libjit was a new layer on top (or bottom, whatever).

http://flickr.com/photos/t3rmin4t0r/384637216/

Cheers,
Gopal
--
If I learn from my mistakes, pretty soon I'll know everything.