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HP Forum Archive 17

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HP-35s tip: Stack review in RPN
Message #1 Posted by Miguel Toro on 20 Sept 2007, 9:04 a.m.

Hi,

This may be known, but here it is: in RPN, you can review the content of the stack without scrolling 
the values through the registers in a way similar as in ALG:

1 Press left-shift MEM.
2 Press Roll down (you will see the menu with the stack registers).
3 Reviews the values with the left/right arrow keys or with the the roll-down/roll-up key.

I find that useful when you want to view the values and be sure not to mess with them 
pressing by mistake any other key or leaving the values in the wrong register.

Regards, 

Miguel

Edited: 20 Sept 2007, 11:45 a.m. after one or more responses were posted

      
Re: HP-35s tip: Stack review in RPN
Message #2 Posted by Arne Halvorsen (Norway) on 20 Sept 2007, 10:23 a.m.,
in response to message #1 by Miguel Toro

Thx, I did not know, but then I dont have read the manual that detailed yet (guess this was not in it). Helpfull, I have been thinking about how to get programs to behave as built in operation regarding stack and lastx register after operation. This helps checking if program behaves as should regarding the stack (done a lot rdn :-)

      
Re: HP-35s tip: Stack review in RPN
Message #3 Posted by Namir on 20 Sept 2007, 11:53 a.m.,
in response to message #1 by Miguel Toro

Cool tip!!! Thanks!!!

Namir

      
Re: HP-35s tip: Stack review in RPN
Message #4 Posted by Walter B on 20 Sept 2007, 12:10 p.m.,
in response to message #1 by Miguel Toro

Thank you! I did not know this so far either.

      
Re: HP-35s tip: Stack review in RPN
Message #5 Posted by Meenzer on 20 Sept 2007, 12:11 p.m.,
in response to message #1 by Miguel Toro

Veeery coool! And it also works in a program, so you don't have to use the EQN environment to get REGX, REGY, REGZ and REGT!!!

            
Re: HP-35s tip: Stack review in RPN
Message #6 Posted by Miguel Toro on 20 Sept 2007, 12:21 p.m.,
in response to message #5 by Meenzer

I looked throughout the manual and it is not really there. So it seems that it is a true undocumented little feature :-)

Edited: 20 Sept 2007, 12:27 p.m.

            
Re: HP-35s tip: Stack review in RPN
Message #7 Posted by Gene Wright on 20 Sept 2007, 12:23 p.m.,
in response to message #5 by Meenzer

Actually, it will work if you go to ANY menu and then press RDN.

Useful to insert a single REGX, Y, Z or T instruction for a RCL stack register step.

                  
Re: HP-35s tip: Stack review in RPN
Message #8 Posted by Stefan Vorkoetter on 20 Sept 2007, 1:38 p.m.,
in response to message #7 by Gene Wright

I don't have my 35s here at the moment, but I wonder if a REGZ instruction (for example) inserted this way has the same checksum as one inserted using EQN?

Actually, I wonder if this is the cause of some of the checksum differences we've been seeing, namely that some instructions can be entered either using EQN or directly (for example, numbers).

Stefan

                        
Re: HP-35s tip: Stack review in RPN
Message #9 Posted by Miguel Toro on 20 Sept 2007, 2:17 p.m.,
in response to message #8 by Stefan Vorkoetter

Example:

-With menu:

H001 LBL H
H002 REGY
H003 RTN

CHK= D045
LN= 9

-With EQN:

H001 LBL H
H002 eqn REGY
H003 RTN

CHK= 8133
LN= 13

So, at least using the menu method, the program is shorter.

Edited: 20 Sept 2007, 2:19 p.m.

                              
Re: HP-35s tip: Stack review in RPN
Message #10 Posted by Gene Wright on 20 Sept 2007, 2:30 p.m.,
in response to message #9 by Miguel Toro

I believe the 4 byte difference is that equations use 3 bytes plus 1 for each character (REGY).

So the REGY in program 1 takes 3 bytes and the REGY in program 2 takes 3 + 4 or 7 bytes.

      
Re: HP-35s tip: Stack review in RPN
Message #11 Posted by Bruce Bergman on 21 Sept 2007, 12:24 a.m.,
in response to message #1 by Miguel Toro

Wow, good find Miguel!

I notice a couple other interesting behaviors. Caveat: these could already be documented, but I just haven't read the whole manual yet.

While in MEM mode, with VAR highlighted, press ENTER. You can now scroll through the basic statistics register values.

While in MEM mode, with PRGM highlighted, press ENTER. You can now scroll through all program labels to see their LN= values.

Also, I notice that using your RDN trick, I don't need to use the arrow keys at all to cycle through the stack; I just keep pressing RDN and it goes through them in sequence. I think that's what you meant in your last comment, though...

Coolness! ;-)

thanks, bruce

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