Timer/ISR setup

I'm looking to perform a periodic task every 20ms. Previously, using an Arduino Mega, I setup a 20ms ISR by setting values in the timer registers (prescaler, timer compare mode, etc.) and performing a timer compare.

I can't seem to find any info on how to perform this function in an Arduino 101. I tried the existing Mega code, and obviously it doesn't work, as the timer registers are not the same. Also can't seem to find how many timers are even available for use, nor a datasheet.

Any idea on how to accomplish this?

Intel has been working on it after the core release, and the library to perform Timero operations is now available through github (ArduinoCore-arc32/libraries/CurieTimerOne at master · arduino/ArduinoCore-arc32 · GitHub) and will be included in upcoming core release.
Please note that the API are not yet validated, so they could (slightly) change before the official core release