Re: Instruction And Data memory

In article <l1l491pei07ncfqlfj2us29hp1fnq2k39k@xxxxxxx>,
speffSNIP@xxxxxxxxxxxxxxxxxxxxxxx says...
> On Mon, 23 May 2005 21:20:46 GMT, the renowned Rich Grise
> <richgrise@xxxxxxxxxxx> wrote:
>
> >On Mon, 23 May 2005 13:56:58 +0000, Ken Smith wrote:
> >
> >> In article <pan.2005.05.22.18.27.37.278277@xxxxxxxxxx>,
> >> keith <krw@xxxxxxxxxx> wrote:
> >> [...]
> >>>Not at all. There is a rather big difference between the two. A modern
> >>>x86 doesn't do well with self-modifying code, but it can. An 8051 OTOH.
> >>>The first is clearly Princeton and the latter clearly Harvard.
> >>
> >> The PIC is a better example for Harvard. The 8051 uses the same bus but a
> >> different command signal. The PIC has a bus just for instuctions.
> >
> >IIRC, I once scoured the PIC data*** - _A_ PIC data*** - to see how
> >hard a lookup table would be. Turns out it's a SOB.
> >
> >Thanks,
> >Rich
>
> Got to be the only micro architecture that requires an application
> note to describe how to implement a LUT.
>
> Newer models are better, BTW, but you still have to be a bit careful
> compared to Von Neuman parts like the HC05/08.

Yeah, the '51 bends the Harvard rules by having a MOVC to do LUTs.

--
Keith
.