BTW:  Not to bring up a new rat hole/new argument, but rather remind people of one of the arguments of the day.  Because of SP or no SP style of calling, in those days the question came out language design of how the stack or register call area was maintained:  Was it/should it be the responsibility of the calling routine or the called subroutine.  Things like Fortran's entry statement and other non-local goto's, co-routines/setjmp/longjmp added fuel to the fire in the argument.

As a language designer/implementor at the time, someone like Steve Johnson and Doug McIlroy were undoubtedly mixed up in the argument and had opinions.  I was certainly too inexperienced then to understand what the fight was about.   But I do remember the fight and how the issues were taught/discussed at CMU when I was a student.  I admit I was quickly sucked into C's way of handling things, as it seemed simple/clear/understandable to me, but not being a language person I probably did not (maybe still do not) value some the arguments for the other side.

Clem