eval - evaluate the circuit given an input

yosys> help eval

eval [options] [selection]

This command evaluates the value of a signal given the value of all required
inputs.

-set <signal> <value>

set the specified signal to the specified value.

-set-undef

set all unspecified source signals to undef (x)

-table <signal>

create a truth table using the specified input signals

-show <signal>

show the value for the specified signal. if no -show option is passed
then all output ports of the current module are used.