26 Oct
2022
26 Oct
'22
4:24 a.m.
On Oct 12, 2022, at 12:01 PM, ron minnich <rminnich(a)gmail.com> wrote:
I know branch and link was in the 360; was it earlier? And ... anybody know who invented
it?
This came up in a risc-v meeting just now :-) My claim is that if anybody knows, they
will be in this group.
Zuse Z4 had instructions to jump to a subprogram and back. Unclear if they were in the
original Z4 (1945) or were added later. Or how it was done.
https://cacm.acm.org/blogs/blog-cacm/247521-discovery-user-manual-of-the-ol…
Turing's ACE (1946) computer had BURY and UNBURY that push and pop a
subroutine's return address from a ptr held in TS31. TS1..TS32 were "temporary
storage" registers each in a recirculating memory (mercury delay line?) with a cycle
time of 32µs. The paper referenced below says BURY and UNBURY were subroutines but I
wonder if they were macros.
From the "Turing and ACE, Lessons from a 1946 Computer Design"
<https://cds.cern.ch/record/263304/files/p230.pdf> paper, "Inventing this
concept in late 1945 was a truly amazing achievement, perhaps inspired by the recursive
function theory which Turing had learnt from the work of Church, and by a slight knowledge
of the nineteenth century work of Babbage."