On May 11, 2016 4:24:09 AM PDT, Peter Zijlstra <pet...@infradead.org> wrote: >On Wed, May 11, 2016 at 07:15:19AM -0400, Brian Gerst wrote: > >> I think he meant the out of line version would be asm, so you could >> control what registers were clobbered. > >Yeah, it might save a few cycles on the call, but given that most >machines should have popcnt these days is it worth the hassle/cost of >duplicating the lib/hweight.c magic in asm (and remember, twice, once >for 32bit and once for 64bit) ?
I was thinking it isn't really very complex code even in assembly as it is super-regular; you can even crib the gcc-generated code if you wish. -- Sent from my Android device with K-9 Mail. Please excuse brevity and formatting.
