I hadn't heard this urban legend before. A stack is certainly manageable without auto-increment/decrement (AID) instructions. In fact Dennis's compiler did not use AID instructions for that purpose. AID instructions are nice for a LIFO stack, in which a stacked item disappears as soon as it's used--as do intermediate results in expression evaluation. But when the stack contains local variables that are accessed multiple times, the accesses are offset from the stack pointer. If AID instructions set the pointer, then the offset of a particular local varies throughout the code. The compiler can cope with that (I once wrote a compiler that did so), but a debugger will have a devil of a time doing a backtrace when the offset of the return address in each stack frame depends on the location counter. AID instructions are fine for sequentially accessing arrays, and in principle Ken's ++ and -- operators can exploit them. Yet idiomatic C typically wants post-increment and pre-decrement instructions--the opposite of what DEC offered. Examples: char a[N], b[N]; char *ap = a; char *bp = b; int i; for(i=0; i<N; i++) *ap++ = *bp++; int a[N], b[N]; int i = N; while(--i >= 0) a[i] = b[i]; Doug