Unverified Commit e10a3463 authored byBrowse files
Optimise `memcmp` for speed
I saw that in other parts of the `string` module iterations over `usize` were used to increase iteration speed. In this patch I apply the same logic to `memcmp`. With this change I measured a 7x speedup for `memcmp` on a ~1MB buffer (comparing two buffers with the same content) on my machine (i7-7500U), but I did not do any real world benchmarking for the change. The increase in speed comes with the tradeoff of both increased complexity and larger generated assembly code for the function. I tested the correctness of the implementation by generating two randomly filled buffers and comparing the `memcmp` result of the old implementation against this new one. I ran the tests and currently currently three of them fail: - netdb (fails to run) - stdio/rename (fails to verify) - unistd/pipe (fails to verify) They do so though regardless of this change, so I don't think they are related.