how to start a multicycle process correctly

The path from "start_sub_process" to "out_sub" has the constraint applied (40 ns)

I think that all paths from start_sub_process shouldn't have the multicycle constraint applied, because it's a 100MHz signal that goes in a slower process. start_sub_process will be high for 4 periods @ 100MHz to be correctly catched by the multicycled process, but the setup requirement remains 10 ns.

Am i wrong?

I modified the constraint given by example:

set_multicycle_path 4 -from [get_fanouts [get_pins enable_reg|q*] -through [get_pins -hierarchical *|*ena*]] to [get_fanouts [get_pins enable_reg|q*] -through [get_pins -hierarchical *|*ena*]] -end -setup

same thing i did for hold requirement.

In this way, i hope, only paths from/to enable_reg are multicycled