Harvard vs. vonNeuman

From: ben franchuk <bfranchuk_at_jetnet.ab.ca>
Date: Tue Sep 28 15:02:07 2004

Andy Holt wrote:

>
> On the CDC6600 - and, for that matter most machine architectures that
> preceded the IBM /360 - the subroutine call instruction writes a jump to the
> return address as the first word of the subroutine and then branches to the
> second. Before Manchester invented "B-lines" (index registers)
> self-modifying code was needed even for indexing.

What about later machines like the PDP-8, that I have used.
The next machine I build I don't plan to have index registers
just simple indirect addressing. I have done one or two designs
in a FPGA but this time I want to use real TTL.
Anybody got a good web link on decimal floating point,I am not sure
how to handle the sign bit with decimal math for adc operations.

> It is almost a definition of a modern architecture that code need not be
> (and often cannot be) self-modifying.
ROM able code does say a lot about how you program your machine.
> Andy

Ben.
Received on Tue Sep 28 2004 - 15:02:07 BST