5 Jan
2016
5 Jan
'16
11:42 p.m.
On Tue, Jan 5, 2016 at 11:46 AM, John Cowan <cowan(a)mercury.ccil.org> wrote:
A PDP-11 Fortran compiler could have followed such a
subroutine call by
a series of branch instructions and had the callee use MARK rather than
RTS to return to the correct point in the jump table.
Could be - I was not there for that one but, I'll have to try to ask one or
two of the designers of the the 11 FTN compiler back end when I see them
next who was. Rich or Dave might know/remember. That said, some of the
folks on the simh mailing list might also remember like Tim or Bob.
That said, IIRC the PDP-11 on chip did not support it, so I suspect the FTN
compiler did not use it. I also know that in the past, when we had talked
about some of the silly instructions that were created in different ISPs
during lunch conversations, I have specific memories of some of the
compiler folks saying they could never figure out PDP-11's MARK either -
hence my comment about few did know how to put it to good use.