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HP 65 program tips - Printable Version

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HP 65 program tips - Ralph - 01-31-2005

Somewhere on the hp65 owner's handbook it stats that when starting program execution from the keyboard pressing [R/S], the first [RTN] is ignored by the calculator and it stops at the second [RTN] found. That's true, but it seems not only the first [RTN] is ignored, also every [g][NOP] instruction found till the second [RTN].

If you try the following program (clear memory first):

LBL A_
5_
RTN_
2_
g NOP_
+_
RTN

Pressing [A] will leave the answer 5, pressing [GTO][A] and then [R/S] will leave 7!

If you try this other program (clear memory first):

LBL A_
1_
RTN

Switch to RUN mode and press [GTO][A] and [R/S]. The calculator passes through A and all following [g][NOP] steps on memory, back to top of memory and stops at [RTN]. If you look the stack contents the number 1 is on both X and Y registers (A has been executed two times).

Supose I'm the LAST one who discovers this...


Was this the "cocked" vs. "uncocked" RTN status? - Gene - 01-31-2005

I think something like this was described back in the 1974/1975 PPC Journal issues.

By the way, if you DON'T have a copy of those from Jake Schwartz on CD, you're really missing a wonderful resource. :-)


Re: Was this the "cocked" vs. "uncocked" RTN status? - Ralph - 01-31-2005

I have the museum CD's, is this Jake Schwartz CD on them?


Link to Jake's CD ROM set of PPC Journals and more! - Gene - 01-31-2005

http://www.pahhc.org/ppccdrom.htm

Quite an impressive set!
Gene