Re: Sleek approach to Register Exchange on HP-29C Message #3 Posted by Matt Agajanian on 16 Mar 2012, 11:43 a.m., in response to message #2 by Jeff O.
Thanks indeed!
I didn't think of your 4-step approach but, on my own, I did ironically come up with the 5-step approach found in the HP-35A's Math Applications book (although I lose the T-register):
RCL N
X<>Y
STO N
CLx
+
BUT, you got me there! Your first algorithm proves to be the winner even if I need to lose T. Even though, in both yours & my approaches, further down the line, provided I don't lose the Z register, the Z register (which is the last T register value) gets pushed back up to T anyway. So, with that in mind, the next pop will save T and copy to Z. Thus, the net effect will be as if I didn't lose T in the first place.
If I can streamline my SR-56/TI-58C progs enough for the 29C, I'd be willing to use your version that preserves both the T and LASTx registers.
Edited: 16 Mar 2012, 12:27 p.m. after one or more responses were posted
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