Author: Tom Kerrigan
Date: 18:44:21 02/15/03
Go up one level in this thread
On February 13, 2003 at 18:04:46, Robert Hyatt wrote: >>This argument isn't going anywhere. We don't have processors where we can turn >>OOOE on and off (or at least we don't know how) and even if we did and OOOE >>provided a significant speed increase, you would fall back on your >>blame-the-compiler position. The UltraSPARC 3 is fast on paper except for its >>lack of OOOE, and it performs like crap, but I suppose Sun's just been slacking >>off on their compiler. > >Sun has been slacking off on their compiler _and_ their processor. The sparc >hasn't >been competitive in several years now... Exactly. >>How is cmov not predication? I guess because it's not called "predication." >Because it is not the same thing. It is just a simple scalar instruction that >tests the >flag register and moves the data if the right condition is set. The effect is >certainly >akin to predication, I would not argue that point... So how is it different from predication? An instruction that executes according to a flag (which is what your description of cmov boils down to) is the definition of predication. >>>I wouldn't mind a G4 at all. In fact, I tried to find a good multiple-cpu >>>PPC machine when I bought my first quad p6/200, but could not find anything >>>that was much beyond vaporware at the time. The processor looks pretty good >>>to me however. >>I suggest you try using one. They're crap. >It depends on your definition of "Crap". >Crap because it is slow? Crap because it has a poor instruction set? Crap >because the >architecture itself makes programming cumbersome? >IE back in the good old days, when the war was 8086 vs the MC6809, the motorola >lost on speed, but had a better architecture, particularly when the 68000 came >along. >The PPC architecture looks to me to be reasonable. Whether the performance is >or not >is another issue of course. The PPC "architecture" (let's say you mean the G4, for sake of argument) is reasonable the same way the K6 was reasonable, because it's at about that level of sophistication. You can like an architecture all you want but at the end of the day you want speed. My favorite ISA is ARM, but I'm not going to run my chess program on a Pocket PC at a tournament, and I can't imagine you'd run Crafty on a Mac, regarless of whether or not its architecture is "nice." -Tom
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.