Re: Old Keys Message #3 Posted by Kiyoshi Akima on 5 July 2006, 2:53 p.m., in response to message #1 by mountain
On the HP-67 and HP-97, P<>S swapped the Primary registers with the Secondary registers. In effect, it swapped registers R0-R9 with R10-R19. Register numbers were only one digit (or one letter), so R10-R19 could not be addressed directly.
Or are you referring to some other machine?
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