Tutorial 25
Checking your TI-83 Plus' Memory via Asm Progam

Introduction
    This tutorial will show you how to create a RAM checking program. This program will make good use of the _Memchk(_Memchk = 42E5h) and _Disphl(Disphl = 4507h) ROM calls.

Programming

.NOLIST
#define equ .equ
#define EQU .equ
#define END .end
#include "ti83PlusAsm.inc"
.LIST

.org 9D95h

    B_CALL(_ClrLCDfull)
    ld hl,Mem ;Load Text
    B_CALL(_puts)
    B_CALL(_Memchk) ;Check RAM
    B_CALL(_DispHL) ;Display contents of HL
    ret

Mem:
    .db "RAM free (bytes)"

.end
END


How the Program Worked
    This is a fairly simple program. The _Memchk ROM call checks the amont of memory available in RAM. It hen stores that value to the HL register. _DispHL then displays the contents of HL on the screen.

New Commands
    _MemChk - Checks amount of memory in RAM, outputs value to hl.
    _Disphl - Displays contents of HL


Conclusion
    This wasn't hard. =) Amount of Free RAM may vary due to hidden system variables not marked dirty. This may alter the Free RAM returned by a few bytes.

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