if you hadn't already known this about the PDP-8

From: cmurillo_at_multi.net.co <(cmurillo_at_multi.net.co)>
Date: Thu Dec 13 02:51:31 2001

Gunther wrote:
>I found this really interesting: The PDP-8 has no concept of a
>stack. It does have sub-routines though. Instead of pushing the
>instruction pointer onto a stack, it's being written at the
>location to which the call is directed (first address of the
>subroutine). Then a return is simply an indirect jump to that
>first address of the subroutine.
>This is hillarious! Wasn't the notion of a stack arond already
>before 1965?

Interesting... I suppose that it had to do with the fact
that the pdp8 was supposed to be affordable...

Roughly 13 years later, the RCA 1802 was introduced; it doesn't
have a fully functional stack either, and in order to call a
subroutine located far away you have to do stack manipulation
yourself, resulting in an 8 or so instruction sequence before
calling and a similar one to return. I hated it because I
was already used to the 8085.

Then, there was the hp 3000 architecture (ca. 1973), which relied
on the stack hardware at all levels.


Received on Thu Dec 13 2001 - 02:51:31 GMT

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