Hi all,

I'm wondering how to access the calculator variables (A, B, C, L1, L2, Str1, etc.) in ASM. I tried going through the 28 days tutorial but it doesn't quite make sense to me.

Thanks

Edit: When in doubt, read this document:

http://education.ti.com/downloads/guidebooks/sdk/83p/83psysroutines.pdf

Older post: Allow me to present this probably quite poor code from Doors CS 4:


Code:
Note that this is TI-83 ASM. For TI-83+ ASM, all the call _routines need to be bcall(_routine)s.

Quick tutorial for RAM vars (they're easier):

Just like anything else in memory, you access calculator variables with a pointer, which means you'd need to know where it is first. The TI-OS includes two b_calls that find variables for you: FindSym and ChkFindSym. The first one is faster but can only find variables that aren't programs, appvars, or groups. If you want to find a variable that's one of those, you'll have to use ChkFindSym.

Either way, you first have to load the name of the program into the nine-byte area called OP1 (so the routine knows what to look for). The easiest way is to store the name as data in the program:


Code:


Then when you actually call the routine, load the label into HL, call Mov9ToOp1 (with rst 20h), and call the appropriate finding routine:


Code:


If it finds the variable, the carry is reset:


Code:


If it's in RAM, B will be 0:


Code:


DE now points to the two size bytes of the variable, which come before the data. If you want to make DE point to the start of the actual data, add two:


Code:


This will also work with any other variable type.

Hope that clears some stuff up.

So, if I wanted to find a list LIST, I would have the following code:


Code:


and if I wanted to read from list LIST, then i would start from DE + 2 in RAM.

Correct?

List are found with ChkFindSym, not FindSym. Also, you don't inline .dbs, unless you weren't. Convention is to put data like that at the end of your program. Otherwise, correct.

What Kerm said. Always put your data at the end of the program (after the RET). Otherwise it'll get run as a sequence of commands, since they're the same thing.

So I am trying to code a calculator lock that utilizes list LIST, which contains the key values. Here is the code I have (doesn't work):

Code:


This indirection is making me dizzy...

Uh, no. It will only get run if the programmer forgets to jump around the data. IMO, randomly scattering data around your program isn't good, but it won't crash your calc if you are careful.

Numbers in lists are stored as 9-byte floating points (tutorial here).

Oh yeah. I forgot >.<
Still, when I run the debugger, ListLoc points at apparently nowhere in particular.

EDIT: after hours of debugging, i finished the program.

That's great to hear, congrats! Perhaps you'll consider uploading it to the Cemetech archives, once you decide it's complete?