Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Technology Stocks : Advanced Micro Devices - Moderated (AMD) -- Ignore unavailable to you. Want to Upgrade?

To: jcholewa who wrote (19742)	11/20/2000 3:06:50 AM
From: Joe NYC	Respond to of 275872

JC, That explains it. Joe PS: Interesting discussion on Anand's BBS forums.anandtech.com

To: jcholewa who wrote (19742)	11/20/2000 10:39:02 AM
From: Daniel Schuh	Read Replies (1) \| Respond to of 275872

Yeah, but I bet if the P4 didn't have Intel's famous NetB*s double pumped 3ghz technology, the rotate would take 8 or 12 cycles instead of 4 or 6. Some casual reader of recondite technical arcana picked up on this a while back in Message 13230330, though that particular poster overestimated the cost somewhat. Well, the document did say "Shifts are relatively much more expensive", and the poster admitted it was just a guess. As Paul DeMone might possibly confess some day, it's hazardous to extrapolate performance from very limited technical documentation. Cheers, Dan.

To: jcholewa who wrote (19742)	11/20/2000 11:37:03 AM
From: TechieGuy-alt	Read Replies (3) \| Respond to of 275872

as ROL is used by hardly any program out there. Err, excuse me, programs must have changed a LOT since I last looked at assy lang and programmed some for embedded systems. bitwise rotate left is (was ?) the usual way to do multiplies by any factor of 2. Additionally, any bitwise masking operations (like reading a bit from a port- very usual in embedded programming at least) is handled with the same instruction. You OR the new bit in the LSb and rotate left to make room for the next one. AJIMHO TG