Author: Robert Hyatt
Date: 08:50:04 03/26/04
Go up one level in this thread
On March 26, 2004 at 09:15:12, Fabien Letouzey wrote: >On March 26, 2004 at 09:13:12, Fabien Letouzey wrote: > >>On March 26, 2004 at 09:07:18, Slater Wold wrote: >> >>>On March 26, 2004 at 08:50:51, Fabien Letouzey wrote: >>> >>>>>>I find it interesting; do you feel like investigating? >>>>> >>>>>Yes. I can, and will. I started looking last nite, but ran out of time. >>>> >>>>It's not urgent of course, but I think we've got something to learn. >>>>For instance a way not to do things for 64-bit platforms :) >>>> >>>>>>One drawback of 64-bit ints and pointers is that they could take more space in >>>>>>memory, but I thought I carefully avoided that everywhere ... >>>> >>>>>I am not sure what's slowing it down. I could clearly see why it might not get >>>>>a huge speedup, but the 10% slow down is confusing. >>>> >>>>I pass many pointers as function arguments (for instance I pass a pointer to the >>>>board everyhere instead of using a global variable). To me an argument is the >>>>same as a local variable, and the slow down is very small on 32-bit platforms I >>>>am sure. >>> >>>This was my first guess. You cannot cast pointers to int, long, ULONG, or DWORD >>>in 64-bit. And there's a whole slew of other things to look at, also. >> >>I don't do any tricks with pointers, I don't even store them in any struct or >>array (only local variables, that's registers or stack). I just pass them as >>argument; no pointer arithmetic ... >> >>>It very well maybe a part of it, but I think investigating the pointers, >>>arguments, and variables is a better place to start. >> >>Well if profiling reveals a clear difference between the 32-bit and 64-bit >>version that would be easy. Of course I am expecting no such thing. >> >>Alternately, I could read the AMD 64-bit recommendations looking for something >>that I do differently. I didn't bother because Fruit does not use bitboards. >> >>Fabien. > >Would there be a reason why, for instance, 16-bit integers would be slower in >64-bit mode? > >Fabien. Yes. 16/32 bit ints require sign-extension. signed things are a problem...
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