Michael Sokolov <[EMAIL PROTECTED]> wrote:
> The other is A4-based data, which you again have stolen from the innocent
users.
Just so everyone is aware of this, we have encountered plenty of compatibility
problems with apps using A4 to point to their globals. (In fact, we put a hack
into PalmOS 3.5 so that these apps will continue to work... but its not going to
stay there forever!!) The last time I checked, the developer had to manually
add calls to save, set up, & restore the a4 register for use of globals in
callback routines (like form event handlers, etc). As long as this is still the
case, then some developers will probably continue to forget, and their apps will
break on future versions of PalmOS because the OS does NOT preserve the A4
register. Plus, if you just point to your globals with A5 instead, then its
easier and more efficient because you don't HAVE to go to any extra work to
save/set up/restore it. So, you aren't really doing your users much of a favor
by allowing them to use A4 for globals in applications.
Another piece of PalmOS history:
The reason that every launch code doesn't support globals is because we needed
to keep these launchcodes FAST. Some are broadcast to every application
installed on the device... as it is the performace can be "poor", but it would
be a lot worse if every one of those apps set up and disposed of its globals.
Applications that want to set up their globals can do so, and using the A5
register to point to them will work just fine.
Regards,
Jesse
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