RCL-57

[pauln]

In the last few months, I have been writing a TI-57 emulator for the iPhone. It's going to come in two flavors, "original" and "rebooted", though only the "rebooted" flavor is currently available.

You can download the current alpha version from this link: https://testflight.apple.com/join/FxfbbK0s

I plan to offer it for free. The source code can be found at: https://github.com/n3times/rcl57

Any feedback is very much appreciated. Thanks!

[Jlouis]

Nice.

Any chance to have an android version some day?

[pauln]

Thank you! Probably not in the short term, unless there is a lot of interest : ) The emulator itself is written in portable C, and I've made the code publicly available so it shouldn't be too difficult to port it to other platforms.

By the way, I don't anticipate much interest in the iOS version either!

As a teenager I did have a TI-57 and I realized, when writing this emulator, that my recollection was a bit rosier than the reality: the TI-57 is quite slow, its screen is quite flickery and the keyboard is not always responsive. (In the rebooted version, I "fix" these issues.)

Though one can write a few interesting programs, it would have been so much better if it had twice the memory.

I wrote RCL-57 mainly as a stepping stone to writing a ROM-based TI-59 emulator. One important consideration, compared to many calculator emulators, is that I wanted to make sure I had a deep enough understanding of the internals that I could show the state of the calculator in the User Interface. For example, RCL-57 shows the user program and a log of the user operations. I could have also shown the registers or the AOS stack. RCL-57 is also 1,000 faster than an actual TI-57 but makes sure that Pauses or the screen blinking on error are not sped up.

Of possible interest for readers of this forum is that, in the rebooted version of the emulator, I've changed program editing to follow HP's way. That is, I show the last entered instruction instead of the next one (which would be typically "00"). I'm more of a TI person, but I have to admit that here HP got it right... For even more fun I've made the display alphanumeric, so it's more like an HP-41C : ) All this in the rebooted mode. Purists will be able to use the original mode which will be like the actual calculator.

I will attach some screenshots.

[pauln]

Some screenshots of RCL-57 with a program computing a sequence of the Syracuse Problem.

                   

[Matt Agajanian]

Sounds fascinating. Would the data registers and program memory be increased? I would think that 224 program steps or more with 30 registers or higher should be a good starting point.

Although I had a 58C (as a upgrade from my 56), I would have liked to see the 58/59 series with fully merged keystrokes to compete with the HP-67/97’s implementation of fully merged keystrokes.

[pauln]

(05-12-2022 04:28 AM)Matt Agajanian Wrote:  Sounds fascinating. Would the data registers and program memory be increased? I would think that 224 program steps or more with 30 registers or higher should be a good starting point.

Although I had a 58C (as a upgrade from my 56), I would have liked to see the 58/59 series with fully merged keystrokes to compete with the HP-67/97’s implementation of fully merged keystrokes.

That's an interesting idea. That would be pretty much like the HP-67. I would settle for 100 steps and 10 registers (instead of 50 and 8 respectively) like the HP-65.

Beating the 50-step barrier may be relative straightforward, as long as one is satisfied with the existing 10 labels (I am).

The difficulty is expanding from 8 registers to 10, preferably dedicated. The TI-57 shares some of the users registers with the AOS stack and the t-register (for conditional branching). Another difficulty is that all of the 256 opcodes are already taken (for example there is an opcode for "RCL 7" and another one for "INV Prd 2") so it's not clear how to fit the required new instructions such as "STO 9".

If I could solve these issues, I would take on the project (100 steps + 10 registers).

With 50 steps, I was able to fit a non trivial program that, given a number, finds the closest fraction. But a full biorhythm program seems beyond its capabilities. There is a biorhythm program in the manual but it requires the user to do a lot of computations by hand.

[Matt Agajanian]

100 program steps/10 data registers… I lived with that on my SR-56. So yeah, I could live with that. And, better yet, all fully merged!

Two things that would sweeten the pot even better are if all 10 registers were available to the user and the t-register is an independent register.

[rkf]

(05-11-2022 09:22 PM)pauln Wrote:  ... By the way, I don't anticipate much interest in the iOS version either! ...

Don't underestimate the curiosity of the people lurking around here! :-)
Since I collect both HP and TI vintage calculators, I have an interest in trying out emulated oldies, too. So I felt free to participate in your TestFlight invitation - and immediately enjoyed the exact reproduction of the original 9.0047463834 Calculator Forensics result of your emulation.

Carry on!

Kind regards, Ralf.

[Didier Lachieze]

This is a nice emulator, it works fine on my iPad mini. I like the way the prefix keys (2nd , INV) are highlighted when pressed. As there is no haptic feedback it helps confirming the key press. And the alphanumeric display of program instructions is a nice improvement over the original TI-57, I like the way it's done, keeping the LED display style.

I have one question: what is the meaning of the arrow close to 'Deg' on the x key? It's not on the TI-57 keyboard layout.

(05-11-2022 09:22 PM)pauln Wrote:  Of possible interest for readers of this forum is that, in the rebooted version of the emulator, I've changed program editing to follow HP's way. That is, I show the last entered instruction instead of the next one (which would be typically "00").

Well, I've been struck by this one while modifying a program : on the TI-57 a new instruction is inserted at the step displayed on the screen, while on your rebooted version it's inserted at the step after, which puzzled me until I realized it was intentional.
I understand why you've changed it, but as I'm using also a real 57 as well as go57c on Android I would like to have the option to keep the original TI-57 program editing for consistency.

[pauln]

(05-13-2022 11:11 AM)Didier Lachieze Wrote:  I have one question: what is the meaning of the arrow close to 'Deg' on the x key? It's not on the TI-57 keyboard layout.

It means the calculator is in Degrees mode. If one presses "2nd Rad", the arrow should move next to the 'Rad' key.

Thanks for the rest of the comments.

The alphanumeric display uses indeed 14-segment LEDs to keep with the style of the era.

I will definitely add some options such as haptic feedback and whether to use HP-style program editing or not.

[pauln]

(05-13-2022 06:41 AM)rkf Wrote:  Carry on!

Thank you!

[Matt Agajanian]

I’m looking forward to the iPad and iPhone versions.

[pauln]

RCL-57 alpha 1.1 is now available. Same link: https://testflight.apple.com/join/FxfbbK0s

I've added a Settings view. See screenshot.

   

[Nigel (UK)]

This looks great. I’ve never owned a TI-57 so I’m having fun seeing what it can (and can’t) do. So far, no problems.

By the way, did you also write RCL-58 and RCL-59? These are/were brilliant programs. I still fire up RCL-58 on my Android phone every so often; RCL-59 (which was even better!) seems to have vanished from the Apple App Store. Is it coming back?

Nigel (UK)

[pauln]

Thank you! I plan to rewrite RCL-59.

With RCL-57 I wanted to try a different approach than the one I used for the original RCL-59. It is ROM-based so it's a true emulator instead of a simulator. The code is publicly available so it could potentially be ported to other platforms (and maintained/enhanced : ) by others. On a more technical side I wanted to use the newer iOS frameworks: it has been 10 years since I wrote the original.

For RCL-59, I plan to incorporate some of what I did for RCL-57. This is something I do on the side but I plan to have some version of the new RCL-59 by the end of the year.

[Dave Britten]

I'd definitely be interested in grabbing an updated RCL-59 for my iPhone. I'm one of those weirdos that likes both HP and TI stuff. (And Casio, and Sharp...)

[DrewNicholson]

(05-16-2022 05:14 PM)Dave Britten Wrote:  I'm one of those weirdos that likes both HP and TI stuff. (And Casio, and Sharp...)

Aloha Dave, who are you calling weird, besides pretty much everyone here? ;-) I never met a calculator I didn't like.

Aloha Paul,

I totally love it!

Mahalo ala nui - which means "thank you very much!"

[Ren]

So...
Is RCL a clone of RPL?

I mean, your main interest in recreating the 57 was to give it RPN, right?
B^)

[pauln]

(05-20-2022 12:00 AM)Ren Wrote:  So...
Is RCL a clone of RPL?

I mean, your main interest in recreating the 57 was to give it RPN, right?
B^)

I know you are kidding : ) but in case anybody wonders, it means of course "Recall TI-57". I borrowed it from my own "RCL-59" and I borrowed that name from an excellent little book:

https://www.amazon.com/Rcl-20-Wiodek-Mie...0951073338

[Werner]

(05-16-2022 03:58 PM)pauln Wrote:  Thank you! I plan to rewrite RCL-59.

Great! My first ever calculator was a 58 (sadly not a 58C..), and I have RCL-59 on my phone.
Gave me a chance to finally peek at the LinAlg routines of the Master Lib to see how they were written. Not so good, I figured, and rewrote them.
On the simulator, mine are 2-3 times as fast as the originals, so I'd like to know how much faster they would be in the emulator. Oh, and they allow solving a 9x9 system ;-).

Cheers, Werner