20 Chapter 2: TI-83 Plus Specific Information
TI-83 Plus Developer Guide Third Release May 28, 2002
Storing and Recalling System Variable Values
Since system variables are located at a fixed location in RAM, an application can access
the contents of a system variable directly. This method is safe only when recalling a
single system variable.
There is also a system routine that copies the contents of a system variable to OP1; the
value in the accumulator determines what system variable is recalled. See SysTok
values in Table 2.8.
RclSysTok Copies the contents of a system variable to OP1.
StoSysTok Stores the contents of OP1, if valid, to a system variable.
Note: An application should not modify the contents of a system variable directly; it should always use
this system routine.
The system variable stored to is determined by the value in the accumulator.
Example: If you want to store -3 in Xmin:
B_CALL OP1Set3 ; Reg OP1 = Floating point 3
B_CALL InvOP1S ; Negate FP number in OP1, OP1 = -3
LD A,XMINt ; ACC = Xmin variable token value
B_CALL StoSysTok ; store OP1 to Xmin,
Example: If you want to recall the contents of Xmin to OP1:
LD A,XMINt
B_CALL RclSysTok ; OP1 = contents of Xmin, -3
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