3 ms·
I doubt those instructions (especially stos* and movs*, respectively matching memset and memcpy) are going anywhere. Intel has even changed their semantics in r
by pbsd 13y ago
I doubt those instructions (especially stos* and movs*, respectively matching memset and memcpy) are going anywhere. Intel has even changed their semantics in recent chips to work on 16-byte or larger chunks, and to have out-of-order memory accesses. Current MOVSB, for instance, should be nearly as fast as SSE/AVX optimized memory transfers.
- userbinator 13y agoI wouldn't say their semantics have changed but certainly their implementation. The fact that Intel used to recommend against using them but now advises the opposite, suggests that scas/cmps (memchr/memset) could be next. In any case, the thought of one machine instruction doing better than lots of carefully hand-written assembly is nice.