84PCE:RAM:D007E0
Synopsis
Official Name: cxCurApp
Memory Address: D007E0h
Length: 1 byte
This area of memory tells what app is currently running, if it is one of the builtin apps. The calculator assigns certain values to each different 'app', be it the graph screen, home screen, etc.
The values assigned here are the same as the keypresses that ordinarily switch to the various apps, so the homescreen is indicated by kQuit, the graph by kGraph, the program editor by kPrgmEd, and so forth. If an "external" app (i.e. Flash app) is running, this should always be set to kExtApps. A full list is given in the section "TI-83 Plus Context Equates" in ti84pce.inc.
This byte can be used in hooks, for example, to distinguish between the various apps. The cxCurApp values are constant, whereas the actual context vectors and possibly even the pages they are located on may change between OS versions.