Hello all,

Even though I've seen the application packs for the 33, I wonder if 49 steps was too limiting? Yes, I realise from the Buyer's Guides, the 33 was meant as a follow-up to the 25. Although the 29C was available along with the 33E/C, wouldn't it've been more competitive to the SR-56 and quite a bit more flexible, robust and capable to have a 98 (like the 29C) or 99 step program memory in the 33E/C?

Edited: 18 Mar 2012, 5:51 p.m.

One could always choose the 34C instead. Actually the 34C is one of my favorite HP's. I like the size, the keyboard and the feel of the unit in my hand. I know that some units had issues but I have collected a few over the years and so far all are in good working order.

Cheers,

-Marwan

As Norm always said, RED LEDDDDS!

I suspect this limitation was imposed by available hardware.
RAM was very expensive back then and adding extra program memory would have meant an extra IC.

- Pauli

Ditto!

O! I C! Oh, I see. Perhaps, since the 33 adds linear regression, that might've left less space for indirect addressing, labels or 49 or 50 more prog steps.

Edited: 18 Mar 2012, 10:45 p.m.

I'd've preferred n! over NOP.

I see your point. Any neutral function could work if you need a placeholder. Even on my SR-56, NOP seems somewhat pointless.

Edited: 18 Mar 2012, 11:16 p.m.

HI.

Although it is a matter of preference, I have always seen references to NOP as placeholders for future program lines insertions. Earlier programmable calculators did not offer program edition, the HP67/97 and the HP34C offered automatic insertion and manual deletion of program lines (not sure about the HP19C/29C). I guess that the NOP is some sort of heritage from 'primitive' assembly programming techniques.

Cheers.

Luiz (Brazil)

In my HP25 and HP33E/C Owner's Handbook, the NOP instruction is used during program editing to overwrite a program step that is no longer needed. The HP-55, HP-25/C and HP-33E/C models could not insert or delete instructions during program editing. You could only overwrite a step with a new instruction. These models also did not support address labels. If you needed to delete a step you overwrote it with a NOP. If you needed to insert steps, you overwrote the step at the insertion point with a GTO which jumped to the next step after the end of the program. You then added the new instructions after the original program (including the overwritten step) and used a GTO to jump back to the step following the inserted (overwritten) GTO. Needless to say, it was usually easier to just rewrite the program. I rewrote many a program on my HP-25 through High School, college and my first job before moving on to a HP-11C which finally allowed me to insert or delete instructions (among other improvements). Amazing!

The SR-56 has the same paradigm: No insert or delete or labels and a NOP to compensate for the lack of all these.

I remember a nice feature in the 56: You can hold down PAUSE and see intermediate results of a running program as long as the key is pressed. It's an ad-hoc debugging aid.

Quote:

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Hello all,

Even though I've seen the application packs for the 33, I wonder if 49 steps was too limiting? Yes, I realise from the Buyer's Guides, the 33 was meant as a follow-up to the 25. Although the 29C was available along with the 33E/C, wouldn't it've been more competitive to the SR-56 and quite a bit more flexible, robust and capable to have a 98 (like the 29C) or 99 step program memory in the 33E/C?

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Given that hardware was way more expensive, and handheld calculators were in the early stages, 49 steps was big back then.

But I am fan of memory, so if 99 steps was possible, do it!