Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!purdue!mailrus!husc6!brauer!fry
From: fry@brauer.harvard.edu (David Fry)
Newsgroups: comp.sys.mac.programmer
Subject: Re: How to use Time Manager
Keywords: HELP WITH TIME MANAGER
Message-ID: <795@husc6.harvard.edu>
Date: 9 Dec 88 12:14:06 GMT
References: <829@drexel.UUCP>
Sender: news@husc6.harvard.edu
Reply-To: fry@brauer.UUCP (David Fry)
Organization: Harvard Math Department
Lines: 71


Here's some code to measure a time interval accurate to 1 ms
from inside an XCMD.  It needs to use global variables, and
since it will be called from within an XCMD, you'll need to
perform some trick to use those globals.  This example use
Lightspeed C 3.0, which makes using globals referenced from A4
easy.

As I said, this example will be accurate to 1 ms.  But if you're
going to be measuring ADB keyboard and mouse events, they can
only be accurate to 5 ms at most, so you can save some processor
load by replacing the PrimeTime(&mytask,1L) calls with
PrimeTime(&mytask,5L) calls.  Then the interrupt will get called
1/5th as often.  Oh, and increment the variable by 5 each time.

I hope this helps...

----------------------------cut here---------------------------

#include "EventMgr.h"
#include "TimeMgr.h"
#include "setupa4.h"

/*
	to be used as part of an XCMD in LSC 3.0
*/

long		increment;
TMTask		mytask;

pascal void MyInc()
{
	SetUpA4();
	/* 
 		SetUpA4() is necessary because MyInc will be called
		as an interrupt and register A4 could point anywhere
	*/
	increment += 1;
	PrimeTime(&mytask,1L);
	RestoreA4();
}

time_something()
{

	increment = 0;
	mytask.tmAddr = MyInc;
	InsTime(&mytask);
	PrimeTime(&mytask,1L);
	RememberA4();
	do {
			/*
				do anything you want between the InsTime
				and RmvTime calls

				of course, you needn't stay in this
				function
			*/
	} while ( !Button() );  
	RmvTime(&mytask);

	/* 
		increment now contains the # of milliseconds
		elapsed time
	*/	
}

David Fry						fry@huma1.harvard.EDU
Department of Mathematics		fry@huma1.bitnet
Harvard University				...!harvard!huma1!fry
Cambridge, MA  02138