On 17/02/2025 05:12, ben via cctalk wrote:
Did any classic computers have a subroutine call as (S++)=PC, PC=(EFA)
as well as the standard call (--S)=PC,PC=(EFA) ?
One could have a virtual stack machine, using helper functions
without having to deal with return addresses on the stack.
On the more than "one stack pointer" in the subject, it was a bit
arbitrary on the PDP-11 (or VAX) as the pre/post indexed indirect
addressing made every register a stack pointer. But this is where I get
hazy between DEC and 68K, and I did a lot more 68K. I'm pretty sure you
could do a move.l PC, An and you could certainly do an indirect jmp
(An), so effectively you could have multiple call stacks if you wanted.
