Survey posted 2005-06-30 03:43 by Jon.

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I have to apologize about the "summer job" part; I didn't mean to exclude anyone in the southern hemisphere!

"I feel so invisible down here. :'("

Thats ok. The winter is pretty poor here atm anyway. lol.

Would have liked a "I dont use my calc at work, but I use it at home" option though. That could have made it more general.

I am indeed using my calculators. I am disassembling the TI-81 ROM (including naming the routines, since the disassembly is already finished (I am really bored right now, since I have temporarily run out of AI ideas :) (& yes, I do program in LISP sometimes))), which involves my TI-92+ for hexadecimal arithmetic & a real TI-81 because the emulator's keys are arranged horribly (since it was not designed to emulate a TI-81).

Ti-81 :D :( Boring, by the way, how old is that calculator

Mine (which has ROM version 1.8K) says "Copyright (C)1991" on the back, so quite old. I am not sure if there were any earlier ROM versions, but my dad's has a later one.

Hmmm... See here.

» TI-81 (1990)
The TI-81, TI's first graphing calculator, was designed for algebra and precalculus. It has since been replaced by newer models which have faster processors, more memory, and popular features such as linking capability and flash upgradability. The TI-81 drew little in the way of third-party games and other programs, since the code must be typed into the calculator by hand.

But it'd be cool to have a total 81 emulator for the 68k calc. Possible?

Sure... no ROM needed... just make it act like an 81 would (like Mac-81 or PC-81).

One could probably do full emulation, because the TI-81 hardware is very simple. Its processor runs at 2MHz, while the HW2 68K's run at 12MHz (with a better processor), so it could theoretically run at full speed. The worst part would be keypad emulation.

Oh yeah, I see what you mean. :)

>> (...(...(...yes, I do program in LISP sometimes)))

I couldn't tell :-).

I am not taking any classes, and I don't use my calculator at work, so I had to vote that it's collecting dust even though I occasionally use it at home for programming purposes...I'm currently trying to figure out how to convert numbers to "base pi" where pi (base 10) = 10 (base pi), pi^2 (base 10) = 100 (base pi), etc...

How on earth can a non-integer base work very well? o.o

Actually, base Phi works quite well. For example, Phi+Phi^-2=2, so 2 in base Phi would be 1.01. You just use digits up to int(base) if the base is not an integer. Unfortunately, I know of no way to get a non-integral number of distinct digits.

I don't know, what about the exponential function e? We use that one a whole heck of a lot for growth/decay functions (shuddering at remembering horrid differential equations problems)

Wrong type of base. You are thinking of a base for logarithms & powers, while the other posts were referring to bases in which numbers are written, although e can be used for the latter, also.

Take Int(mod(#,pi)) (or whatever syntax on your calculator of choice) to get the next digit (it gives the 1's place first). Then, replace # with (#-[the digit you got])/pi. Stop when # gets to 0. The only problem is that it does not support digits after the "decimal" point in base pi, which would be necessary to properly represent normal integers & such, so this is just an approximation.

I think mod( doesn't allow non-integer modul\=\i. At least it doesn't on the TI-89.

I'm a high school intern at Microsoft. A significant proportion of the interns are Linux users, as are many who work in my department (mouse & keyboard drivers/support software).

It works on both my TI-86 & my TI-92+, so I think it should work on the TI-89 also.

Oh, boy, Linux users working at Microsoft. I guess the Gentoo guy brought along a bunch of friends, right?

BTW, compiling TiLP leads to a "registry missing" error on my SuSE 9.3 box. Any help or RPMs of the TiLP packages newer than a year ago would be helpful.

I recently wrote a "Base Converter" program that can convert base n to base m, for all n and m where n and m are positive integers up to 62. For example, it can parse your name into a base 10 number (since you can write out your name in base 62). Nifty, huh?

Base 62 seems wasteful if you are just encoding your name. Base 27 would seem to be a better choice (so it would allow spaces between first & middle & last). Also, why not allow up to base 95? ASCII has enough characters (or 94 if you do not want to use spaces) (though I suppose it might be hard to type some characters on some calculators).

It wasn't really intended for name encoding. It was intended for general purpose base conversion and compression. However, base 62 isn't wasteful because it means you can type in both lower and upper case. (Sorry, no spaces; what if there were a space at the end of the number?) Anyway, what I have been using it for thus far is as an image compressor. I wrote a program that looks at a group of pixels, parses them into a 33-bit binary number (the largest binary number possible without losing precision), which the program then converts into a base 62 number. Using this method, you can compress the entire picture into a string that takes up about 500 bytes of memory.

In that case, nifty.

At any rate, a larger base would result in a smaller string, at the possible expense of taking longer to encode (since bases over 63 would require an extra bit, causing the divide routine to run 1 extra iteration). Plus, base 64 would be particularly convenient because you could use a simple lookup string (rather than the base-conversion formula) to encode/decode it. Just my 0.16 bits worth.

Wow, great compression method! How large were the pics to begin with?