Verifying The Os Version - Texas Instruments TI-89 Developer's Manual

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ahead of time which commands it will execute. Commands that will cause a
problem are those such as Graph or DspTbl. These commands, along with
several others, cause a context switch which the app must handle. See the
example app in section 8.4 Interfacing with TI-BASIC (specifically the
runningBASIC flag) for how to handle the context switch.
For an example on executing a command with side effects, see section
17.2 Working with the Graph Application.
8.5.

Verifying the OS Version

Version 2.04 of the AMS introduced F-Line instructions to call the API. This
requires an app to run on Operating System Version 2.04 and later but can
reduce every API call from six bytes to two bytes. This is the standard calling
mechanism when using the tiams.h include file. Accessing AMS global variables
requires the use of the Access_AMS_Global_Variables macro and each AMS
global variable reference requires six bytes plus the overhead from the
Access_AMS_Global_Variables macro.
In order to ensure your app is running in AMS 2.04 and later put a call to the
OS_NeedMinimumVersion macro at the top of your app's event handler. It
needs to be called before any F-Line instructions (an AMS 2.04 feature) are
executed. Its format is:
OS_NeedMinimumVersion ( frame , major , minor )
frame — The name of the variable which contains the address of your
major — Major version number of required OS level.
minor — Minor version number of required OS level.
For example, if you have a pointer to your app frame named pAppObj:
pFrame pAppObj = (pFrame)&appObj;
Then at the top of your event handler entry point call:
OS_NeedMinimumVersion(pAppObj, 2, 4);
This checks for OS release 2.04 or greater. If the OS is an earlier version, a flag
is set in the app's ACB disabling the app so it will not appear in the app's menu.
This macro returns to the OS without letting the rest of the event handler run.
Be aware that some F-Line calls may not be immediately apparent. If an app
uses a library or API routine (say a long divide or any API call) in its local variable
initialization, an F-Line may be inserted to call the library routine and is always
used to call the API.
TI-89 / TI-92 Plus Developer Guide
Chapter 8: Integrating a Flash Application
application frame.
Not for Distribution Beta Version January 26, 2001