Harvard v. von Neumann

Sridhar Ayengar ploopster at gmail.com
Fri Dec 12 17:41:07 CST 2008


Chuck Guzis wrote:
>> What was the mechanism for transferring data between the stack and the 
>> program space?
> 
> As far as I can remember, there was no prohibition on two entries in 
> the PRT describing the same physical address space--one as program, 
> the other as data.  That would seem to kill the Harvard Architecture 
> idea, no?

But, the data could only be operated on from the stack, right?  So, if 
you wanted to write a self-modifying program, wouldn't you need to have 
two entries in the PRT, similarly to what you've suggested, and then 
wouldn't you also need to push the elements of the array containing the 
program data onto the stack, operate on them, then pop them off the 
stack and back into the array space, thereby allowing the code to run?

Or am I missing something?

Peace...  Sridhar


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