Hello all.

I'm a little rusty on my HP-34C programming so, please fill me in.

I tried to record STO x 2 and STO x .2 into program memory. STO x 2 recorded properly BUT STO x .2 only recorded the . (decimal point). I don't remember my HP-34C limitations but, was this restriction of addressing registers .0 to .9 only for storage/recall program instructions (thus, register arithmetic for address .0-.9 is not available in program memory)?

Edited: 7 May 2012, 10:31 p.m.

Yep, that is correct: register arithmetic limited to R0 to R9, does not apply to R.0 to R.9. On the other hand, it also applies to RI and R(i) (indirect addressing), so if you use STO (+,-,×,÷) (i), you can access R.0 to R.9 with values from 10 to 19 stored in RI.

Cheers.

Luiz (Brazil)

One quote from the manual (from the Museum DVD):

Storage Register Arithmetic. Registers Ro through Rg in your HP-34C
are used for the direct storage register arithmetic operations described in
Solving Problems With Your Hewlett-Packard Calculator. However, all
storage registers (Ro through Rg, R.o through R.g, and I) can be used to
perform indirect storage register arithmetic (we'll cover this subject later,
in section 7).

So, to answer your question, you can't use .0 - .9 for storage register arithmetic. Either in program mode or in manual mode.

Cheers,

-Marwan

From the HP-34C Owner's Manual, page 22*:

Storage Register Arithmetic. Registers R₀ through R₉ in your HP-34C

are used for the direct storage register arithmetic operations described in

Solving Problems With Your Hewlett-Packard Calculator. However, all

storage registers (R₀ through R₉, R_.0 through R_.9, and I) can be used to

perform indirect storage register arithmetic (we'll cover this subject later,

in section 7).

^{* You can find it in the Museum's DVD #1.}

HA! Pretty funny. All posting at the same time. Gerson and I even provided the same reference! Although my cut and paste did not come out as cleanly as his (edited?) version.

Edit: We both even mention the Museum DVD.

Cheers,

Marwan

Edited: 7 May 2012, 11:04 p.m.

Hello all.

Sorry if I'm not posting this under the correct heading. Thanks to all of you for the recap!

Quote:

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Although my cut and paste did not come out as cleanly as his (edited?) version.

---

It did require some editing like formatting and replacing a few 'g' amd 'o' with '9' and '0', respectively. The searcheable and editable PDFs starting from the Museum DVDs version 7.00 are a blessing, despite the occasional need for minor manual adjustments. (Thanks, Dave!)

Cheers,

Gerson.

Nothing wrong with where you posted. An you are welcome.

Cheers,

-Marwan

Thanks!

I was in advantage, but in the wrong circumstances: I wrote by heart. 8^(

Cheers.

Luiz (Brazil)

Edited: 8 May 2012, 2:42 a.m.

The reason for the limitation is that they use a single byte for each program line, so there can only be 256 instructions, including merged codes. Offering register arithmetic for more registers would have pushed them over the limit. They used 255 of the 256 codes, with one left over.

The 41C went to two-byte instructions for many of the register operations to avoid having this limitation.

Quote:

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The 41C went to two-byte instructions for many of the register operations to avoid having this limitation.

---

Same with the HP-15C, most instructions need just one byte, a few others need two (generally the most specialized or infrequently used ones).

Regards from V.

Hello Luiz,

I only quoted the manual, so did Marwan who also added some words to answer Matt's question. Your concise reply, however, is complete and need not be complemented by any quotation from the manual. But you are a teacher! :-)

Cheers,

Gerson.

Too true! I learn far more on this forum than I ever have the opportunity to contribute. Thank you to everyone for that!

Cheers,

-Marwan

Excellent point. That per-instruction byte count is the item I usually overlook.