Hi Jacques, On 15.08.2013, at 16:42, Jacques Mony wrote:
> Hello, > > After going through the archives, I read an interesting thread regarding > unimplemented instruction set from PowerISA 2.06. The specific instruction > that seems to be called by AIX is stxvd2x, from VSX Instruction Set (new in > 2.06 as I can understand). > > How do one start to implement a instruction sub-set? Where to start? I see > there are helpers, TCG, etc… is there a tutorial that explains where to > start? I already know it will have to support new encoding forms (XX1-form , > XX2-form…) which is not being used yet (afaik), but for the rest, I’m a bit > lost. There is a tiny bit of documentation, but mostly it's all about reading code. I think a good place to start is a patch set that implements instructions. Check out this one from Aurelien: https://lists.gnu.org/archive/html/qemu-devel/2013-04/msg02569.html There is also some documentation available at the QEMU wiki: http://wiki.qemu.org/Documentation/TCG I also did a talk on TCG last year that should give you a high level idea on how it works: http://chemnitzer.linux-tage.de/2012/vortraege/1062 Just get yourself through these and try to figure out what's going on. Keep in mind that TCG is a JIT, so you have 2 phases: 1) translation (guest -> tcg -> host code) 2) execution (host code gets executed) If you still have questions left after that, please feel free to ask again :). Alex