read_rtlil <<EOT
module \top
wire input 3 \A
wire width 2 input 2 \B
wire width 2 input 1 \S
wire \Y
cell $pmux \my_pmux
parameter signed \S_WIDTH 2
parameter signed \WIDTH 1
connect \A \A
connect \B \B
connect \S \S
connect \Y \Y
end
EOT
assertpmux