Answer:
It's completely up to the sentencing judge. If you were on probation for petit larceny and then committed GRAND larceny (a felony crime), the judge could reasonably assume you had not learned your lesson - revoke your petit larceny probation and send you behind bars for the remainder of the sentnece - AND then - you would still face court action lfor the Grand Larceny. My guess is that you're looking at perhaps a year or so - at the very least, least a couple of months.