Four types of RPN

[htom trites]

(09-08-2014 06:00 AM)walter b Wrote:  

(09-08-2014 05:33 AM)htom trites Wrote:  There are some more obscure variations, especially of the top of the stack on a drop:

• top copy
• top is zeroed (HP-35 does this until T has a non-zero value)
• ...
  

What's the difference to top copy then??

d:-?

xyzt + becomes (x+y)zt0, not (x+y)ztt

Different than shortening the stack, there's a value there and it's 0 (vs t)