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I'm trying to write a BASIC poke and peek equivalent for the TI-83+ to experiment. I'm trying to figure out how to read the values from user variables (A,B,C,θ). From what I've read I have to use the OPs to access the variable information, but I haven't come across ways to change user vars. For peek, I would like to put the output in a variable so TI-BASIC programs can use it.

This is the code I have so far:

Code:

#include    "ti83plus.inc"
#define     progStart   $9D95
.org        progStart-2
.db         $BB,$6D
start:
   ;get poke address
   b_call(_ZeroOP1) ;reset op1
   ld hl,op1+1   ;set hl to the address of the location of op1s var name (a)
   ld (hl),'a' ;set a to the op1s var name (the address stored in hl)
   b_call(_RclVarSym) ;set op1 to the var name and value
   ld hl,op1+9 ;set hl to the address of the location of op1s var value. first nine bytes is for a var name
   push hl
   
   
   ;get poke value, same thing except we are accessing var b
   b_call(_ZeroOP1)
   ld hl,op1+1
   ld (hl),'b'
   b_call(_RclVarSym)
   ld de,(op1+9) ;we want the content at this address, not the actual address
   push de
   
   pop hl ; Im just swapping hl and de
   pop de ; I read somewhere that de changes or something, thats why i pushed it in the first place
   
   ld (de),hl ; putting the value at address in hl into the address in de
   
   ret
 


I'm using this assembler.
I just learned z80 asm, so any pointers (hehe) would be useful!
Whoops. Can't load HL into DE's address.
  
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