Gyro Integration Easy-C Implementation

I am using a Vex Robot to prototype Team 47 FRC Robot this season using Easy-C Pro to switch between both bots. Chief Delphi has a white paper “Working the Angles:” authored by Jim Zondag, Team#33 - Killer Bees that I am attempting to implement. This paper shows a simple technique for gyro integration. The gyro_angle(void) function is called from Process_Data_From_Master_Up() every 26.2 msec. A simple calculation is performed. Other C functions are operated/completed and I know the loop will eventually terminate in some holding loop function until the next interrupt starts the next loop again.
How does this correlate to Easy-C implementation? If I place the function in a while loop, won’t the function integrate multiple times and get different results.
What Easy-C implementation should I use with the gyro to make sure it only get’s implemented once during the 18 msec(?) loop?