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Hi, I saw that in some program in hte hp 41 program library section, this function : X<>T or X<>Z

how do I do this on my calcualtor? I tried to figure it out on my calculator but didn't find how to :S

Thank you :)

Hi, I saw that in some program in the hp 41 program library section, this function : X< >T or X< >Z

Good question. That one's rather arcane, and I had to learn it as well, about eight years ago.

[SHIFT] I (gives < ; check the plate on the back of the HP-41)
[SHIFT] J (gives > ; check the plate on the back of the HP-41)
[ALPHA] (wait for the HP-41 to show 'X<> __', prompting for a two-digit register number)
. (The HP-41 shows 'X<> ST _', now prompting for a stack register X, Y, Z, T, or L)
Z ('X<> Z' is displayed or executed)

"X< > " is an open-ended function, found in CATALOG 0. Completion with stack register X will form an "X< > X" function that can be programmed or executed, useful only as a no-op that consumes clock cycles. It is also noted that "X< > Y" is not displayed the same as the built-in
"X< >Y", and likely does not have the same op-code.

If the [SHIFT] key is pressed instead of [.], indirection "IND" is invoked. [SHIFT] [.] will allow exchange with a storage register whose number is in a stack register.

Among the RPN calc's, only the HP-41 and HP-42S offer direct exchange between stack registers. The HP-42S will display "X< > ST Z", because 'Z' can also be the name of a variable.

Voyager-series connection: On the face of the HP-15C, the open-ended "X< > " replaced "X< >I" and "X< >(i)" on the face of the HP-11C, opening a valuable position and creating 27 unique functions completed with {0-9}, {.0-.9}, {A-E}, I, and (i). Sharp thinking; sound engineering.

-- KS

Edited: 6 July 2010, 1:45 a.m. after one or more responses were posted

Thank you very much! :)


Search for "Exchanging X and Any Register" or everything you always wanted to know about the HP-41 (but were afraid to ask).

Best regards