Private end code for 41 CX


Hello. Sometime back I was able to get some help from this forum to disable the 'Private' end code for my 41. Since the card reader took a dump, it was necessary that I get back into the programs I had written.

Now, I again, come to this forum and ask your assistance. I would like to know how to place a 'Private' code back into the end of the two main programs that I use. I need this as a personal safeguard mainly, to avoid inadvertently placing some steps into the program that shouldnt be there, as well as stopping anyone from also doing the same thing.

Any help would be greately appreciated.

Thank you




if you have a card reader or tape drive or disc drive,
you could simply save your programs private,
then reading them from the medium.

Twenty years ago I wrote two small assembler
routines to make a program private and vice versa,
but for this you need a ROM simulator or a RAM Box.

So here's a nice method to produce a PRIVATE program
if you have the 'byte grabber' assigned to a key.

1. In PRGM mode, backarrow the END of your program.
2. Key in: RCL IND 66
3. then: RCL 77
4. Perform two times BST
5. Activate USER mode
6. Press the key where you assigned the byte grabber
7. Delete the resulting ALPHA line
8. Deactivate USER mode (optional)
9. GTO..

This information was taken from the HP-41
Synthetic Quick Reference Guide by Jeremy Smith.

I leave it as a nice puzzle to you to find out what the
byte grabber is, and how you can assign it to a key;-)




Raymond, thank you for your response. Is the 'byte grabber' the same as the Byte Jumper mentioned in the 41 synthetic programming?

I dont mind a puzzle, but a non puzzle answer would be real nice right about now.

I am checking the items you mentioned now.



Raymond, looking at the byte grabber instructions, it seems I would need to do a master clear of program memory to assign the BG to a key.

Since I do not have any means to store the programs as it is, other than having them written down in longhand, I would really like to be able to get the byte grabber assigned without having to do a memory clear.

Is there another way to accomplish this?





there are several options. The easiest
is shown near the bottom of this text.

1. If you have either
- a CCD ROM , PPC ROM or similar,
- a HEPAX module
- access to some kind of RAM box
- ...

you could assign the byte grabber code or
manipulate the bit in the END directly.

2. If you have an HP-71B, and
- your files on an HP-IL drive

you could read the file(s) into RAM,
then manipulate them with the POKE function of the HP-71,
then write them back to the medium.

But the easiest way is as follows:

Since you unprotected your HP-41 programs,
just write them to disk/tape with WRTPV,
then delete them on the HP-41, and read them back.

I'd suggest the following method:

Use WRTA (WriteAll) with a suitable name in ALPHA.
I'd do this twice, with different names in ALPHA,
so you have a backup of your backup.

Then clear your HP-41, and make the byte grabber
Save this via WRTK, having a suitable name in ALPHA,
then restore your calc with READA,
again with the appriorate name in ALPHA.
After that, you can use READK to restore your byte grabber.
But note that this overwrites your other
exisiting key assignments.

However, now you can grab bytes at will,
but be careful, the byte grabber is a nice
tool to wipe out memory if used carelessly;-)


BTW: You shouldn't use so many threads for the same subject;-)


Raymond, I have read that wiping memory was one way of assigning the BG, but there is another way that has more extensive steps to it that does not need a memory wipe.

Do you know what that is?


Check out the articles forum for a quick easy way to remove PRIVATE.

I posted it there quite some time ago...


>Check out the articles forum for a
>quick easy way to remove PRIVATE.
yes, but Paul wants to *set* PRIVATE again.

>I posted it there quite some time ago...
You mean this thread?



Steve said "Check out the articles forum for a quick easy way to remove PRIVATE.

I posted it there quite some time ago..."

Steve, I was the one that originally posted sometime back asking how to remove the PRIVATE instruction. Your response was perfect then.

Now I need to once again manipulate the 41 to *add* a PRIVATE at the end of the programs. I do not have any storage devices, so I was hoping that there was a Bug that would allow me to make a regular .END. into a PRIVATE.

I would like to be able to do this without doing any Memory Lost things, like making a Byte Grabber needs.

Do you know of a way?



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