Messages in this thread | | | Date | Sun, 10 Jan 1999 00:26:08 +0000 | From | Jamie Lokier <> | Subject | Re: Can and should the kernel HZ value be changed? |
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On Thu, Jan 07, 1999 at 01:13:16PM -0500, Richard B. Johnson wrote: > On Thu, 7 Jan 1999, Chris Wedgwood wrote: > > Oh -- and gcc sucks rocks at geenrate long long code. Not helped by > > the fact ia32 is a horribly register starved processor. > > Not so. Long long stuff is as good as anyone should expect on a 32-bit > machine. It's a lot better than 680xx stuff I've seen from compilers.
> [code example]
I've used GCC's long long stuff, and found it acceptable but not great. I was about to write about how terrible it is, but I just tried some tests and found the code to be quite acceptable.
There are some optimisations it's not at all good at, but on the whole it's ok. I have written time critical code which uses long long for a few things, where appropriate. Then again, I did tweak the compiler to produce better code in the cases triggered by my program.
Just don't expect to divide two long longs efficiently -- the ia32 doesn't have good hardware support for that, which is why it's out of line.
-- Jamie
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