Sounds like a neat idea - I hope someone can finish it!

If I knew either of those programming languages I might try but I don't know them and don't have time to learn them with all my classes...

Looks great! I'll gladly help, but I'm still learning ASM so I don't think I could do anything now. But later on, why not?

You should propose this to Kerm Martian... (If he has enough time.)

I wish I had time. :P I'm drowning in work atm. :(

Nice idea! Great job. I would love to help, but I don't know C or asm.

I might be willing to help if this is turned into a collaborative project. I do know some z80 asm though I do not know any C I have been planing on learning C or a C derived language for some time now.

Why doesn't he just put it up on Sourceforge. Then, it becomes a collaborative project.

It should be great to see this project complete, but i guess that in order to help u must have a lot of knowledge in ASM, C, and developing CAS.....

If i had enough time i would be pleased to help.. but i guess that i had to study a lot the source to be able to help.

that's cool! I think it's a worthwhile endeavor... however, I would like to point out that a similar piece of software, known as ZoomMath has been released on http://www.zoommath.com I've downloaded, installed, and tried out their free version App4Math and the interface, although shockingly different at first, turned out to be quite intuitive. I highly recommend anyone continuing Sebastian Theiss' Typhoon try out the interface used in App4Math in the hopes of implementing something like it in Typhoon.

Oh, and btw, if anyone has any information regarding the security features of App4Math or ZoomAlgebra, that information would be appreciated. ;)

ZoomMath is a nice App indeed. However, it has a very narrow focus on some specific problems that arise in algebra class. With Typhoon I tried to be a bit more universal. Besides, Typhoons interface is close to beeing complete. What needs to be completed is most of the simplification: Up to now the App can determine derivatives, deal with very long integers (about 500 digits) and do some basic simplification.

to quote some of the documentation for it:

"Zoom Algebra is so easy to use, you can focus on the math instead of trying to remember which keys to press. Without Zoom Algebra, to type ał, you need to use the funky ^ key. In Zoom Algebra, just type a then press 3. In Zoom Algebra, you type problems the way they look!"

OMG no funky exponent key? How amazing. </sarcasm>

Appreciated, I'm sure, but also illegal.

You have to do some real digging to get past his protections. For a calculator application, it's very well done. But not perfect.

Sebastian, could you explain what is left to program? And what C compiler are you using? SDCC?

Whats left to program is most of the symbolic simplification. Besides I originally planned to integrate support for units and unit conversion, but I haven't prepared anything like that yet. Please send me an e-mail and I will happily provide details about the compiler. It's not SDCC but some more efficient compiler. I can also provide some information on how the realize symbolic simplification.

This does sound like a very promising project, which I would love to help with, but currently I just don't have the time. I hope someone can finish it.

Another question: how are you using C? Are you only using it for the math side of things (due to how hard/annoying it is to hand-code math in asm), or is it the main language?

I used asm for the whole GUI (softkey menu, dialog boxes, etc.), the memory manager that uses the whole free memory of the calculator as a heap and provides the c-functions free and malloc, to wrap some of the OS functions, and for some basic routines that work with very long integers. I used C for the higher level stuff, as this is very annoying to code by hand and would make development even more time consuming): "pretty-printing" of equations, very long integer and rational number math, simplification, derivatives, etc.

Are you using a commercial compiler? Because I don't think any of the free Z80 compilers out there are significantly more efficient than SDCC, are they?

But are z80 C compilers ever efficeint. I guess it's okay here since math isn't speed-intensive, but C definitely isn't the way to go on z80 in most cases.

C compilers AREN'T that bad, but it does the job if memory efficiency isn't your biggest thing.

I've used z88dk and i'm not aware of any more efficient compilers then a one that costs money.

I used the C compiler from HI-TECH (http://www.htsoft.com/), which is - in my opinion -the best one around. They drastically dropped the price recently, but its still about 200$. C is not only "not bad", it was the only way for me to make such a huge project at least realistic, given the time I had. Unfortunatly I nevertheless didn't manage to complete it due to beeing chronically short on time lately...

Sebastian, have you used some of the free C compilers, such as SDCC and z88dk, for any "serious" development? I'd like you to let us know how the compilers compare to HI-TECH's compiler in terms of code size, data size, and speed.