Silly HP-41C Question

[smp]

Hi all,

I am happily getting familiar with my newly acquired HP-41C prior to getting my 41CL when Monte has another batch. (I had an HP-41C way back in the day, but it fell into disuse and was regrettably sold off to a collector long ago.)

So, today I dug out my old copy of Practical Astronomy with Your Calculator, and made a brute force program to calculate the date of Easter. No efficiencies at all, and probably the most laughable RPN program ever, but I got it in and it works.

The curious thing for me is that when I say XEQ EASTER, the screen clears and the flying goose symbol appears, but it does not move at all for the few seconds it takes the calculator to go straight through the list of instructions.

This program is just a series of simple in-line calculations with STOs and RCLs, INTs and FRCs, + - * and /. No loops.

What makes the flying goose symbol move while a program is executing?

Thanks,
smp

[hth]

(07-30-2016 11:37 PM)smp Wrote:  This program is just a series of simple in-line calculations with STOs and RCLs, INTs and FRCs, + - * and /. No loops.

What makes the flying goose symbol move while a program is executing?

Thanks,
smp

It moves one step when it passes a label.

[smp]

(07-31-2016 12:58 AM)hth Wrote:  It moves one step when it passes a label.

Ah! The program has no labels, except for the very first line. That's it, then.

Thanks very much.

smp

[rprosperi]

(07-31-2016 01:29 AM)smp Wrote:  

(07-31-2016 12:58 AM)hth Wrote:  It moves one step when it passes a label.

Ah! The program has no labels, except for the very first line. That's it, then.

Thanks very much.

smp

One thing you can do in a program with no looping is insert a label when you complete each partial calculation (or phase, or section, etc.) so while running, you can see the goose progress through the phases of the overall problem. This provides something to watch so one is not wondering if anything is happening.

They can all be the same label number since there is no branching. Also, IIRC, there are some synthetic label statements that execute faster than normal ones, but this is only a distant and very hazy memory so this may not be correct (but checking into synthetics will help to re-acquaint you with the 41 - I recommend Wickes' green book).

[hth]

(07-31-2016 02:26 AM)rprosperi Wrote:  They can all be the same label number since there is no branching. Also, IIRC, there are some synthetic label statements that execute faster than normal ones, but this is only a distant and very hazy memory so this may not be correct (but checking into synthetics will help to re-acquaint you with the 41 - I recommend Wickes' green book).

No, there are no such labels, you can make the program faster by omitting labels and have precompiled jumps (works as long as you do not make indirect calls or want the A-J local labels on the top rows), but that is tricky and is sure to make your poor goose never take off.

Wickes' book is very old. It was written before the byte grabber was found (F7), instead it uses the byte jumper (F0 I think). I would not recommend it as the primary source.

"Extend your HP41" is a better primary source.

Håkan

[rprosperi]

(07-31-2016 02:47 AM)hth Wrote:  Wickes' book is very old. It was written before the byte grabber was found (F7), instead it uses the byte jumper (F0 I think). I would not recommend it as the primary source.

"Extend your HP41" is a better primary source.

Certainly as the original book on synthetics, Wickes' book is dated, but I enjoy the way it explains the discovery and building of the jumper, etc. Later books (Jarret's and Wlodek's in particular) definitely explain more powerful techniques, but I still enjoy Wicke's style best. Tastes vary...

[hth]

(07-31-2016 02:21 PM)rprosperi Wrote:  

(07-31-2016 02:47 AM)hth Wrote:  Wickes' book is very old. It was written before the byte grabber was found (F7), instead it uses the byte jumper (F0 I think). I would not recommend it as the primary source.

"Extend your HP41" is a better primary source.

Certainly as the original book on synthetics, Wickes' book is dated, but I enjoy the way it explains the discovery and building of the jumper, etc. Later books (Jarret's and Wlodek's in particular) definitely explain more powerful techniques, but I still enjoy Wicke's style best. Tastes vary...

I like it too, and it is such a remarkable book that was available so short after the release of the HP41, about one year?

It is well worth studying, but more discoveries were done after it, and the system grew with extended memory, HP41CV and the HP41CX, as well as many other things. By the time of "Extend your HP41", lots of internal documents had been made available by HP, allowing for further insights, though it focuses on the user code side and the system.

[smp]

Here's another silly HP-41 programming question:

Some available programs I see have a special prompt character they use that looks like a capital T but rotated 90 degrees counterclockwise so that it appears like a vertical line with a horizontal line pointing to the right from the middle of it.

Can anyone tell me how I get that character? I've hunted for it, but I cannot find it as an alpha, or shifted alpha character.

Thanks in advance...
smp

[Sylvain Cote]

(08-11-2016 11:16 PM)smp Wrote:  Here's another silly HP-41 programming question:

Some available programs I see have a special prompt character they use that looks like a capital T but rotated 90 degrees counterclockwise so that it appears like a vertical line with a horizontal line pointing to the right from the middle of it.

Can anyone tell me how I get that character? I've hunted for it, but I cannot find it as an alpha, or shifted alpha character.

Thanks in advance...
smp

To see the append character, you need to be in PRGM mode, then in ALPHA mode, type the gold key (SHIFT) then the letter K

Sylvain

[smp]

(08-11-2016 11:36 PM)Sylvain Cote Wrote:  To see the append character, you need to be in PRGM mode, then in ALPHA mode, type the gold key (SHIFT) then the letter K

Sylvain

Thanks very much, Sylvain!

This is not the first time that I've been tricked by looking for a character or a function, and then find that HP does not show it as a character, but instead spells out the name.

I'm embarrassed, but I'm glad that I asked, because I really wanted to know the answer.

Thanks again.

smp

[rprosperi]

(08-11-2016 11:59 PM)smp Wrote:  This is not the first time that I've been tricked by looking for a character or a function, and then find that HP does not show it as a character, but instead spells out the name.

If you find yourself working on 41 stuff with no manual handy, check out this awesome on-line version here: http://www.greendyk.nl/hp41c-manual/index.php

There are several others as well, just look one level up.

[smp]

(08-12-2016 12:45 AM)rprosperi Wrote:  If you find yourself working on 41 stuff with no manual handy, check out this awesome on-line version here: http://www.greendyk.nl/hp41c-manual/index.php

There are several others as well, just look one level up.

Hi Bob,

Thanks. Yes, I know about that. It's not the lack of a manual that is my problem right now, but the sheer mass of information available!

It's a bit of a curse to already know a bit about this, I think. I kind of know what's going on, and then I stumble or get stuck on the least little thing.

I'll tell you about one other time: I am keying in a program from the archive, and I'm more than half way through and I come upon the instruction E4. I get totally stumped, because I'm thinking somehow it is a hexadecimal byte! How do I enter that? I totally did not get that it really was the keys EEX 4 until a day or two later, when I remembered that EEX 4 would show up on the display as 1E4, but someone had gone back in and saved a byte off the instruction. BAH!

Anyway, I am having a good time with it all, learning it all over again. Thank goodness there is an understanding community here that I can ask my embarrassing questions!

smp

[Dieter]

(08-12-2016 01:37 AM)smp Wrote:  I'll tell you about one other time: I am keying in a program from the archive, and I'm more than half way through and I come upon the instruction E4. I get totally stumped, because I'm thinking somehow it is a hexadecimal byte! How do I enter that? I totally did not get that it really was the keys EEX 4 until a day or two later, when I remembered that EEX 4 would show up on the display as 1E4, but someone had gone back in and saved a byte off the instruction. BAH!

Wait until you come across a line with a single "E". ;-)

(08-12-2016 01:37 AM)smp Wrote:  Anyway, I am having a good time with it all, learning it all over again. Thank goodness there is an understanding community here that I can ask my embarrassing questions!

No problem, go ahead.

Dieter

[Sylvain Cote]

(08-12-2016 06:05 AM)Dieter Wrote:  Wait until you come across a line with a single "E". ;-)

Or something like STO Q or some string that are created using the byte grabber

(08-12-2016 06:05 AM)Dieter Wrote:  No problem, go ahead.

Yep! were here.

Sylvain

[smp]

Hi Dieter and Sylvain,

Yes, I get it. Synthetic programming presents another area with sooo much material available. I am well aware that it's there, and I'll be trying my hand with it, too. For my first level refresher, I have attempted to stick with "normal" HP-41 programming, and remembering about memory limits, and dealing with what SIZE is needed to try out a given program.

Access to so much information through the MoHPC as well as some other sites (as pointed out by folks here) all at once presents its own "problem." In the beginning, so to speak, the discovery was going on and everyone was sharing new information in an ongoing fashion, so it could be consumed and experimented with in an ongoing fashion, eventually building up. Right now for me, getting back into the HP-41 is like standing at the base of a mountain of information all available all at once! It is a bit daunting, but I am having great fun.

Thanks for being there to answer my questions!

smp

[rprosperi]

(08-12-2016 12:02 PM)smp Wrote:  Right now for me, getting back into the HP-41 is like standing at the base of a mountain of information all available all at once! It is a bit daunting, but I am having great fun.

LOL... Watch out for rock slides...

Just ask questions as you need to; we've all been there and obscure topic-by-topic, at least some of us still are...

The 41C system is a uniquely high mountain due to it's immense popularity, long life and extensive options. Could be as much 41 "stuff" out there as there is "stuff" for all other models combined. But take comfort in knowing no one, not even here, knows it all...