Can steps per mm be decimal value? (1 reply)

In Marlin, I read that the steps per mm parameter takes up to second decimal point. But, how's this implemented as pulses?
My understanding is steps per mm = number of pulses generated for 1 mm.
How is it possible to generate decimal number of pulses? Or are the decimals accumulated or rounded?
Kindly help me with this!
Thanks in advance!