13 Dec
2001
13 Dec
'01
2:51 a.m.
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.
carlos.
T