How to generate a random 16 bit number , having fixed number of "1" s in it . Like 16bit number with 5 "1"s in it, example "0000-1010-1110-0000"

UVM
3

In reply to dave_59:

getting error

Error -[NYI-CSTR-SYS-FTC] NYI constraint : sys function calls

System fucntion calls are not yet implemented in constarints.
Remove the function call or if possible replace it with an integral state
variable assigned in pre_randomize()

I have not assigned anything in pre_randomize.

What could be the issue ?