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HP-35s Memory Management
07-10-2017, 07:10 PM
Post: #2
RE: HP-35s Memory Management
(07-10-2017 04:24 PM)Matt Agajanian Wrote:  There is a peculiar structure that I'm even perplexed as to say "What were they (HP) thinking." And it's the memory register structure of the 35S. I can see that registers A-Z, like the alphabet, can be addressed by a simple A, B, C keystroke, but why did the classic 00-800 register addressing be convoluted to both an indirect addressing scheme plus on the less than zero number scale.

Sorry, but you're wrong here.

(07-10-2017 04:24 PM)Matt Agajanian Wrote:  The way I see it, which makes much more logical sense registers 00 to 800 could have been addressed in the conventional manner with A-Z registers being designated the negative number addressing.

That's exactly how it works. ;-)

If you want to access the variables A...Z indirectly, that's address –1 to –26.
Addresses from 0 and higher are used for the large "indirect" memory area.

So –4 STO I, and then RCL (i), recalls variable D.
And 50 STO I, then 123 STO(i), stores this number in register #50.

A = –1
B = –2
Y = –25
Z = –26
R000 = 0
R001 = 1
R002 = 2
R800 = 800 (if available)

(07-10-2017 04:24 PM)Matt Agajanian Wrote:  For indirect addressing, to retain conventional methods, if the I or J register contained a positive value, as usual, registers 0-800 could be accessed.
To accessss variables indirectly, -1...-26 in the I or J register would access variables A...Z.

Once again: that's exactly how it works.
But why don't you just try this on your own 35s?

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HP-35s Memory Management - Matt Agajanian - 07-10-2017, 04:24 PM
RE: HP-35s Memory Management - Dieter - 07-10-2017 07:10 PM

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