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Windowing the alpha register is still under discussion and will be implemented somehow. Scrolling will not.
The companion to aSTO is aRCL which has to be done in alpha mode or from a program. It might be a useful addition to allow a range of numeric registers be stored from and recalled to alpha, at least two for the full display length. To be negotiated...
A short explanation: Until now, registers are not tagged as containing alpha or integer or HMS data or whatever. So a RCL always interprets the contents as a real number with strange effects.
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Jake,
Alpha is - in a way - the ugly duckling in this project. It took some effort to get in even the standard alpha operations of the 42S. It isn't complete yet.
Answer 1: As Marcus mentioned, alpha scrolling is waiting for implementation, so the respective description on page 52 of the recent documentation is only wishful thinking so far (though it shows our plans). The sample string of page 24 (v1.17) was carefully keyed in and documented in parallel :-)
Answer 2: Whatever you store using alphaSTO, you may recall with alphaRCL. We've also added a new command alphaRC# for appending numbers to the string as well. Please check and play, it's working fine IMHO.
Walter
Edited: 14 Apr 2011, 3:12 p.m.
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As has been mentioned alpha-RCL is needed. There simply isn't space in our registers to have a flag indicating alpha data or not.
We might be able to squeeze this into reals with a bit of trickery but there is no chance for integers which also support alpha STO and RCL operations.
Alpha characters are stored as their byte values first character highest. The number of characters varies in integer mode based on the current word size. The function that does this is basically:
z = 0
n = #characters per register
for i = 1 to n
z = (z * 256) + alpha[i]
return z
Take some alpha data and reduce it modulo 256 to extract the characters again.
- Pauli