At 7:22 AM -0400 2001/07/15, Paul Nevai wrote:
>I know that currently SysTicksPerSecond () == 60 on POSE and 100 otherwise.
>My question is, if there are any plans to have any Palms where it is NOT 100.
>Any predictions?
The value returned by SysTicksPerSecond() changes according to the version of the Palm
OS you're running, and whether or not it's running inside POSE. Currently, the value
returned is a hard-coded constant selected during compilation of the ROM, so for
example, it's "safe" to call it once at the beginning of your application, stick the
value into a global variable, and reference it from that point forward in your app.
This avoids the overhead of a trap dispatch on every call, which can substantially
improve performance in tight timing situations.
However, at some point in the future, Palm and/or our Licensees may begin to release
devices which vary their clock speed according on what the device is doing at the time
(a.k.a. processor-cycling) to provide better battery utilization and longer life. In
this situation, the API might return different values according to the speed of the
CPU at the time of the call, thus the aforementioned global variable optimization
would no longer be appropriate.
Whether or not it's a good idea to dynamically vary the ticks-per-second on a device
is really a topic for another discussion. This is not an announcement that anyone is
actually doing it or planning on doing it... only that it has been discussed and that
it could happen... and that you really should just call the API every time you need
the value.
Regards,
Jim Schram
Palm Incorporated
Partner Engineering
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