Re: [Nolug] Centos

On Thu, Oct 27, 2011 at 12:18 AM, Ron Johnson <ron.l.johnson@cox.net> wrote:
[snip]
> You seems to be confusing modern CPUs with the 8088 or 80386SX (which most
> here will remember had data busses half of the register width), since a
> 64-bit data bus moves 64 bits from cache just as fast as it moves 32 bits.
It's true that it moves bits from the cache just as fast,
but I'm sure you're missing something here...

256k of SRAM holds half as many long mode instructions as short mode
instructions that can be held in that same amount of cache, because
more bits of the cache are consumed by a larger operand.

There are instructions that have data dependencies on bits in the
operand, for example SBB, these are not simple transforms based on
corresponding bits in the two or three operands, there are more
logical "steps" for each bit.

Width of the bus is important, but only one factor

--
-JH
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