HP Forum Archive 14

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HP29C - DSZ ISZ Question Message #1 Posted by Mike T. on 8 Mar 2005, 5:19 p.m. I have never owned an HP29C (nor given the prices on e-bay am I ever likely to own one either) but would like to know if the operation of the DSZ/ISZ instructions on the HP29C/HP19C is similar to the DSE/ISG functions on the HP11C - obviously in the case of the HP29C/HP19C the test is against a zero value, but did the HP29C use the fractional and integer parts of the I register in the same was as the HP11C (and HP34C) or was it was it altogether simpler? Thanks. Mike T.

Re: HP29C - DSZ ISZ Question Message #2 Posted by Andrés C. Rodríguez (Argentina) on 8 Mar 2005, 6:04 p.m., in response to message #1 by Mike T. I don't have a 29/19 either, but have used a 29C for a short while many years ago. If I recall correctly (I apologize in advance if I'm wrong), as the test value was zero and as the step was always one, the fractional part is always zero´. For comparison, in the HP41 any register used for ISG/DSE operations has the format: iiiii.fffcc where i is the initial or current value, fff the final value and cc the step.

Re: HP29C - DSZ ISZ Question Message #3 Posted by Bram on 9 Mar 2005, 2:54 p.m., in response to message #2 by Andrés C. Rodríguez (Argentina) Small addition: the fractional part doesn't need to be zero. It's just being ignored.

Re: HP29C - DSZ ISZ Question Message #4 Posted by Mike T. on 11 Mar 2005, 4:10 p.m., in response to message #3 by Bram To summarize - the fractional part of the value in R0 is ignored (and left unchanged?) while integer part is incremented/decremented and next instruction is skipped if the result is zero. Please correct me if I'm wrong! Many thanks for the feedback. Mike T.

Re: HP29C - DSZ ISZ Question Message #5 Posted by Bram on 14 Mar 2005, 7:16 a.m., in response to message #4 by Mike T. fractional part is indeed left unchanged and of course the test is done on the integer part only.

Re: HP29C - DSZ ISZ Question Message #6 Posted by Mike T. on 14 Mar 2005, 5:37 p.m., in response to message #5 by Bram Thank you...

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