ISG/ISZ switchover
04-17-2021, 08:06 PM (This post was last modified: 04-17-2021 08:27 PM by Matt Agajanian.)
Post: #1
 Matt Agajanian Senior Member Posts: 1,082 Joined: Dec 2013
ISG/ISZ switchover
Hi all.

Since ISZ has been replaced with ISG, what is a programming code that is the equivalent of ISZ?

Thanks
04-17-2021, 11:14 PM
Post: #2
 Paul Dale Senior Member Posts: 1,839 Joined: Dec 2013
RE: ISG/ISZ switchover
There isn't an exact equivalence.

Pauli
04-17-2021, 11:40 PM (This post was last modified: 04-17-2021 11:41 PM by Matt Agajanian.)
Post: #3
 Matt Agajanian Senior Member Posts: 1,082 Joined: Dec 2013
RE: ISG/ISZ switchover
In that case, is there a programming trick?

I’m thinking something like this:

Say you want to loop five times:

Place 0.00400 in the loop register.

That way 0 to 4 is five times. Thus when ISG increments the loop register to 5, 5 is great than 4 (.004), so the loop would exit without executing the procedure/equation a sixth time.

Logical?
04-17-2021, 11:44 PM
Post: #4
 Thomas Okken Senior Member Posts: 1,894 Joined: Feb 2014
RE: ISG/ISZ switchover
If you just want to execute a loop n times, wouldn't you be using DSZ, not ISZ? In that case, you can use DSE instead of DSZ:

Code:
5 STO 00 LBL 00 [...] DSE 00 GTO 00
04-17-2021, 11:51 PM
Post: #5
 Matt Agajanian Senior Member Posts: 1,082 Joined: Dec 2013
RE: ISG/ISZ switchover
True. ISG’s gotta be good for something though. Didn’t want to stuff ISG in the back of a drawer ignored and never to be used.
04-17-2021, 11:58 PM
Post: #6
 Garth Wilson Senior Member Posts: 621 Joined: Dec 2013
RE: ISG/ISZ switchover
I don't see which calc we're talking about; but if it's the 41, Angel's WarpCore module has ISLEX, Increment and Skip if Equal on the value in X.

04-18-2021, 12:59 AM
Post: #7
 Thomas Okken Senior Member Posts: 1,894 Joined: Feb 2014
RE: ISG/ISZ switchover
(04-17-2021 11:51 PM)Matt Agajanian Wrote:  True. ISG’s gotta be good for something though. Didn’t want to stuff ISG in the back of a drawer ignored and never to be used.

You use ISG when you need to count up, not down. But DSE saves a few bytes if you just want to execute a loop n times, and don't care what the value of the loop counter is. (Or if you specifically need it to be n, n-1, ..., 2, 1.)

So if the loop counter should go from 5 to 1, use 5 STO 00 ... DSE 00; and if the loop counter should go from 1 to 5, use 1.005 STO 00 ... ISG 00.
04-18-2021, 08:13 PM
Post: #8
 vassilisprevelakis Member Posts: 100 Joined: Mar 2014
RE: ISG/ISZ switchover
(04-17-2021 11:58 PM)Garth Wilson Wrote:  I don't see which calc we're talking about; but if it's the 41, Angel's WarpCore module has ISLEX, Increment and Skip if Equal on the value in X.
If we are talking about the HP-41, then there is the 7ISZ (and the corresponding 7DSZ) from the card reader ROM.

**vp
http://www.series80.org
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