Self-modifying code

[Allen J. Baum]

[]
>In article <1087 at ficc.UUCP> peter at ficc.UUCP (Peter da Silva) writes:
>I have a question:
>
>	Why are an Icache plus a Dcache better than just
>	a big shared cache as big as both?

In terms of hit/miss ratios, a unified cache is clearly better. However, in
terms of effective access time, a split I/D cache is better. This is because
both can be accessed simultaneously, instead of one having to wait for the
other to finish. If both are getting accessed simultaneously (which should
happen 40% of the time, if Loads/Stores account for %40 of instructions), then
this more than offsets the increase in miss ratio.

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