[WP-34s] Swap question

[Tugdual]

I'm having some difficulties to understand how the "pure" P.FCN swap function (looks like two opposite arrows one on top of the other with no register indication).

Is that used to swap two non stak registers like R11<->R12?
What would be the keyobaord entry? Apparently it would only accept XYZT but expects 4 letters?

Finally is it possible to have indirect swap?
Something like:

Code:

R10=8, R11=9 R8=3, R9=4
SWAP ->R10, ->R11
would end up with R8=4 and R9=3

Edit:
Ok found the command P.FCN<-> page 113 of doc 3.1.
So that's not what I'm looking for.
Is there a way to swap registers and indirect registers?

There is still R-SWAP but a bit cumbersome with the required real value parameter.