Messages in this thread | | | Date | Thu, 26 Feb 2004 22:16:34 -0500 | From | Bill Davidsen <> | Subject | Re: Intel vs AMD x86-64 |
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Timothy Miller wrote: > > > Nakajima, Jun wrote: > >> Yes, that's the very reason I said "useless for compilers." The way >> IP/RIP is updated is different (and implementation specific) on those >> processors if 66H is used with a near branch. For example, RIP may be >> zero-extended to 64 bits (from IP), as you observed before. >> > > This is obviously an extremely minor nit-pick, because we're talking > about one instruction here with an interpretation that is far from > obvious, but given that there are now only two architectures which > support x86-64, did Intel choose to do it differently from AMD because > it was poorly defined, or because it wasn't important enough to want to > impact the efficiency of the design?
How about because they messed up trying to clone the instruction set? Never attribute to malice what can be explained by stupidity. <-(quote) > > There are people who would go way out of their way to get a 5% > improvement in performance or decrease in size. If using 66H with near > branches could in some way do that, they would really really want to use > it. This is why I'm curious.
-- bill davidsen <davidsen@tmr.com> CTO TMR Associates, Inc Doing interesting things with small computers since 1979 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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