Contemporary books (incl. TAoCP Vol. 1 IIRC) don’t place return addresses on a stack or in a register at all: you’re generally told to modify the operand of the

Contemporary books (incl. TAoCP Vol. 1 IIRC) don’t place return addresses on a stack or in a register at all: you’re generally told to modify the operand of the jump instruction at the end of the procedure you want to call then jump to its entry point. It took a while before reentrancy was even recognized as a possibility, let alone used (by humans or compilers) by default. I remember reading that the call stack was invented as an implementation device for recursion as introduced in Algol, but I can’t recall how that claim was sourced.