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LastXY Register for WP34S
11-30-2014, 10:37 PM (This post was last modified: 11-30-2014 10:43 PM by PANAMATIK.)
Post: #3
RE: LastXY Register for WP34S
From my point of view, I cannot easily agree to the statement "Implementing such a feature is just impossible on the 34S"

I do know the value of consistency in programming. But an Undo feature imo would not break rules, but just add a new one. Lets get into it. The solution would be to generate 2 new registers like L and K, perhaps named LX,LY, not attached to any letters on the keyboard. The LastXY Undo register would consume just a few RAM bytes in the physical processor memory, about 16 bytes or double with complex numbers. If you dont have left this amount, then you could double purpose or sacrifice 2 to 4 general purpose registers. Before every dyadic instruction the operands could be stored into it, thats easy. By recalling it, there would indeed happen a new kind of stack lift. But this is just a reverse copy back into the X and Y registers. It should not considered as a stack operation at all. The problem with the ambiguity of RCL U and RCL 2 could be solved by a new Sequence, RCL CLx for example, which is afaik not yet occupied.

But again, I know that from the programming side there must be considered some more things. However: not impossible!

Addendum: I just recognized, that your 'impossibility' statement refers to storing the whole memory. Sorry! So still there is your statement "I dont think thats easy!"
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Messages In This Thread
LastXY Register for WP34S - PANAMATIK - 11-30-2014, 08:51 PM
RE: LastXY Register for WP34S - brouhaha - 12-01-2014, 05:10 PM
RE: LastXY Register for WP34S - Bit - 12-01-2014, 06:48 PM
RE: LastXY Register for WP34S - Paul Dale - 12-01-2014, 09:29 PM
RE: LastXY Register for WP34S - PANAMATIK - 12-01-2014, 10:11 PM
RE: LastXY Register for WP34S - Paul Dale - 12-01-2014, 10:26 PM
RE: LastXY Register for WP34S - Paul Dale - 12-01-2014, 10:29 PM
RE: LastXY Register for WP34S - PANAMATIK - 12-01-2014, 10:46 PM
RE: LastXY Register for WP34S - PANAMATIK - 11-30-2014 10:37 PM
RE: LastXY Register for WP34S - Paul Dale - 11-30-2014, 11:34 PM
RE: LastXY Register for WP34S - BarryMead - 12-01-2014, 05:44 AM
RE: LastXY Register for WP34S - Dieter - 12-01-2014, 06:56 AM
RE: LastXY Register for WP34S - Paul Dale - 12-01-2014, 09:08 AM
RE: LastXY Register for WP34S - PANAMATIK - 12-01-2014, 11:07 AM
RE: LastXY Register for WP34S - Bit - 12-01-2014, 01:57 PM
RE: LastXY Register for WP34S - PANAMATIK - 12-01-2014, 07:12 AM
RE: LastXY Register for WP34S - walter b - 12-01-2014, 06:45 PM
RE: LastXY Register for WP34S - PANAMATIK - 12-01-2014, 07:28 PM
RE: LastXY Register for WP34S - walter b - 12-01-2014, 09:14 PM
RE: LastXY Register for WP34S - BarryMead - 12-01-2014, 09:15 PM



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