Offscrpt

OFFSCRPT is an appvar used by the TI-OS to run an assembly program when the calculator turns off. There is also another appvar called ONSCRPT that runs code when the calculator powers on. ONSCRPT is less stable than OFFSCRPT, nad it is possible to do what ONSCRPT does using an OFFSCRPT appvar. The TI-OS runs the code in the appvar from $8001.

Some applications that use this appvar are:

• CalcUtil
• DoorsCS
• TI's Startup App
• zStart
• Krolypto

These applications use a getKey hook to run something on startup (like the ONSCRPT appvar, but more stable).

To install an OFFSCRPT appvar, a program or application must create the appvar with bcall(_createappvar) and set bit 1 of (iy+33h) to indicate that an OFFSCRPT appvar is installed. To uninstall the OFFSCRPT, the OFFSCRPT appvar must be deleted or bit 1 of (iy+33h) must be reset, or both.