On Tue, Dec 28, 2021 at 1:45 PM Bart via lazarus < lazarus@lists.lazarus-ide.org> wrote:
> @Juha: can you please comment on my possible improvement using PopCnt > instead of a multiplication with ONEMASK. > I confess I didn't remember what PopCnt does. I checked from the net. FPC implements it as internproc. function PopCnt(Const AValue : QWord): QWord;[internproc:fpc_in_popcnt_x]; I guess it translates to one x86_64 instruction. Is it implemented for all CPUs? I found this: https://gitlab.com/freepascal.org/fpc/source/-/issues/38729 If it works everywhere, good. It looks like another good optimization for this highly optimized function. I will patch the function using unsigned types where applicable. > I will keep the loop variables unsigned though. > Yes, thank you. Regards, Juha
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