- move the PSL.AC comment to the fault handler
- stop testing for zero-sized ops. after several minutes of package building there were no copyin calls with zero bytes and very few copyout. the semantic of returning 0 in this case is preserved
- shorten exit paths by clearing %eax earlier
- replace xchg with 3 movs. this is what compilers do. a naive benchmark on EPYC suggests about 1% increase in thoughput thanks to this change.
- remove the uselss movb %cl,%al from copyout. it looks like a leftover from many years ago
Details
Details
- Reviewers
kib - Commits
- rS338967: amd64: clean up copyin/copyout
Diff Detail
Diff Detail
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