The Importance of Terminology's Quality

[Arne Vajhøj]

Piet van Oostrum wrote:
>>>>>> Arne Vajhøj <arne at vajhoej.dk> (AV) wrote:
>> AV> Robert Maas, http://tinyurl.com/uh3t wrote:
>>>> John W Kennedy <jwke... at attglobal.net> wrote:
>> JWK> Into the 60s, indeed, there were still machines being made
>> JWK> that had no instruction comparable to the mainframe BASx/BALx
>> JWK> family, or to Intel's CALL. You had to do a subprogram call by
>> JWK> first overwriting the last instruction of what you were
>> JWK> calling with a branch instruction that would return back to
>> JWK> you.
>>>> That's not true, that you needed to do that, that there was no
>>>> other way available. The subroutine linkage I invented for S.P.S.
>>>> (Symbolic Programming System, i.e. IBM 1620 assembly language) was
>>>> to reserve a 5-digit space immediately before the subroutine entry
>>>> point for storing the return address. So the caller needed to know
>>>> only one address, the entry point, and do both store-return-address
>>>> and jump relative to that address, rather than needing to know both
>>>> the entry point and the last-instruction-JUMP-needs-patch address
>>>> as independent items of information.
> 
>> AV> CDC Cyber did something very similar.
>> AV> Not very recursion friendly.
> 
> Actually, the CYBER way wasn't too bad. IIRC the CYBER had a subroutine
> instruction that stored the return address in the location that the
> instruction referenced and then jumped to the address following that
> location. To implement a recursive procedure you started the code of the
> procedure with saving the return address to a stack.

It was of course doable.

Else Pascal would have been hard to implement.

Arne