|Re: [WP34S] Register use by functions.|
Message #2 Posted by Paul Dale on 11 May 2012, 8:28 p.m.,
in response to message #1 by Chris Tvergard
As a rule, internal functions do not make any changes to your state. At least unless that is the whole purpose of the function.
Register I is the complex equivalent of last X (L). Thus, complex operations change I, but nothing else should. J and K hold statistical distribution parameters -- refer to the manual for details as they vary, these are never changed. A, B, C & D are either general purpose or part of the stack. X, Y, Z, T & L are part of the stack and last X.
You three examples in turn:
Norml takes the mean from J, the variance from K and does the appropriate statistical calculation.
RAN# uses special internal state and accesses no registers.
ISG uses the register you give it as an argument and no others.