On Fri, 2016-07-29 at 06:19 +0530, Richard Henderson wrote: > This, I'm not so keen on. > > (1) The helper, since it writes to registers controlled by tcg, must be > described to clobber all registers. Which will noticeably increase memory > traffic to ENV. For instance, you won't be able to hold the guest register > holding the address in a host register across the call.
Ah I wasn't aware of this. How do you describe such a clobber ? Can I describe specifically which one is clobbered ? I didn't think TCG kept track of the vector halves but I must admit I'm still a bit new with TCG in general. I noticed other constructs doing that (passing a register number to an opcode), what do I do to ensure the right clobbers are there ? > > (2) We're going to have to teach tcg about 16-byte data types soon anyway, > > for > the proper emulation of 16-byte atomic operations. Is anybody working on this already ? I thought about that approach as it would definitely make things easier for that and a couple of other cases such as lq/stq. Cheers, Ben.
