3 ms·
pcmpxstrx is a lot more powerful than rep cmps. I'm lukewarm on pcmpxstrx too, but for a different reason: I'd prefer the effort to go into more general purpos
by pcwalton 9y ago
pcmpxstrx is a lot more powerful than rep cmps.
I'm lukewarm on pcmpxstrx too, but for a different reason: I'd prefer the effort to go into more general purpose, highly flexible SIMD instructions (which is thankfully happening now with AVX 512).
- eddyb 9y agoWhat do you think about Cray-style vectors, which are coming back in the form of ARM SVE and the RISC-V V extension? At least the latter claims code compiled once is compatible with all possible hardware configurations, from the start (by way of giving the CPU a "remaining iterations count" and having it reply with how many it can do for the chosen vector lane shapes). IMO, if it does end up working that well in practice, it does put all of the various incompatible versions of packed SIMD extensions in a pretty awkward spot - could we have skipped all of MMX, SSE, AVX, NEON, etc. versions with technology that has been around for almost half a century?
- pcwalton 9y agoSounds like a good idea to me. Seems similar to how GPUs work, which is generally a good path to follow.