HP 42S Programming


Hi all,

I just came across a quadratic formula program that that I do not know how to enter. One of the lines is STO: ST Z and another line is simply :

Can anyone help.


Bob Demers


Hi, Bob;

the HP42S, as the HP41, allows the contents of the X-register to be directly sotred in any of the stack registers (as you probably know).

When you press [STO][.] in the HP41, you can add any of the following: [X], [Y], [Z], [T] or [L] (no need to press [ALPHA]. In the HP42S, you should press [STO][.] (wrongly posted as [shift], orange key) and locate the equivalent register is the softkeys: [ST X] for X-register, [ST Y] for Y-register and so.

If you want to use a valid register as for an index (IND) with [STO], in the HP41 you´d use [STO][shift] (golden key)and select a numbered register, or [STO][shift][.] and any stack-related key, as mentioned above. In the HP42S, the sequence should be [STO][.] and the softkey [IND] plus any valid register. If you choose either a numbered or a named register, simply idnetify it after the [IND] softkey. For a stack register identificator, you should press [STO][.][IND] and [.] again to invoke the stack-related softkeys again. I have no calculators in hands right now, so please, forgive me if I'm adding a senseless sequence.

One of the lines is STO: ST Z and another line is simply :
I don´t recall having the ':' as a separated operation; could it be an ALPHA sequence, like
02 ":"
I don't know where did you take the listings from, but could you add the complete listing here for us? Is it in the HP42S manual?

Hope you succeed.

Luiz (Brazil)

Edited: 16 July 2005, 1:40 p.m. after one or more responses were posted



Wow, that was fast. The program was taken from this site and I have included the link below.

Thanks for your very fast response.

Bob Demers



Hi, Bob;

it seems to me that the ':' is, in fact, a division symbol (÷). In this case, the STO÷ ST Z is keyed in with:

[STO][÷][.][ST Z]
The other occurrences of ':' in the program (step #05 and step #08) should also be keyed in accordingly, with [÷].

Hope this is correct (I'm not home yet to test the program).

Best regards.

Luiz (Brazil)

Edited: 16 July 2005, 1:41 p.m. after one or more responses were posted


That's it!!


Bob Demers


Thanks Bob and Luis,
I've choked on that dang *:* for months ! !


I'm glad that I'm not the only one!!



Hi, all;

I`m home now and I see that I wrongly used [STO][shift] for the HP42S all of the times where [STO][.] is the correct keystroke sequence. Please, read again my posts above, in this thread, if you did not get to the correct sequence:

My first answer (post)
My second answer (post)

Thank you all and, please, forgive me.

Luiz (Brazil)

Edited: 16 July 2005, 1:52 p.m.

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