history of the 4-level stack

[axd1967]

(09-11-2014 02:39 AM)John R Wrote:  

(09-10-2014 12:45 AM)Jeff_Kearns Wrote:  I probably would have used postfix on store if we had more than 10 storage cells (0-9), but "STO N" seemed much more easily understood than "N STO".

It would seem that in a four-level stack, prefix notation (STO 1) does have one extremely important advantage over postfix (1 STO): the former preserves all four stack values (since the register number is never placed on the stack), while the latter would destroy the value in the T register (since the stack would lift when the register number was keyed in).

On the other hand, postfix allows to use computed register addresses (think of indirect addressing, but then on some machines that is also available).