yosys/tests/arch/gowin/init.ys

read_verilog init.v
read_verilog -lib +/gowin/cells_sim.v
design -save read

proc
flatten
synth_gowin -run coarse:

# check if all init values are handled
check -assert -noinit
# check if every flop mapped correctly
select -assert-count 1 t:DFF
select -assert-count 1 t:DFFC
select -assert-count 1 t:DFFCE
select -assert-count 1 t:DFFE
select -assert-count 1 t:DFFN
select -assert-count 1 t:DFFNC
select -assert-count 1 t:DFFNCE
select -assert-count 1 t:DFFNE
select -assert-count 1 t:DFFNP
select -assert-count 1 t:DFFNPE
select -assert-count 1 t:DFFNR
select -assert-count 1 t:DFFNRE
select -assert-count 1 t:DFFNS
select -assert-count 1 t:DFFNSE
select -assert-count 1 t:DFFP
select -assert-count 1 t:DFFPE
select -assert-count 1 t:DFFR
select -assert-count 1 t:DFFRE
select -assert-count 1 t:DFFS
select -assert-count 1 t:DFFSE

delete
design -load read

# these should synth to a flop with reset
chparam -set INIT 1 myDFF myDFFN myDFFE myDFFNE

# async should give a warning
# sync should synth to a mux
chparam -set INIT 0 myDFF*S* myDFF*P*
chparam -set INIT 1 myDFF*R* myDFF*C*

proc
flatten
synth_gowin -run coarse:

# check the flops mapped as expected
select -assert-count 1 t:DFF
select -assert-count 1 t:DFFC
select -assert-count 1 t:DFFCE
select -assert-count 1 t:DFFE
select -assert-count 1 t:DFFN
select -assert-count 1 t:DFFNC
select -assert-count 1 t:DFFNCE
select -assert-count 1 t:DFFNE
select -assert-count 1 t:DFFNP
select -assert-count 1 t:DFFNPE
select -assert-count 0 t:DFFNR
select -assert-count 0 t:DFFNRE
select -assert-count 2 t:DFFNS
select -assert-count 2 t:DFFNSE
select -assert-count 1 t:DFFP
select -assert-count 1 t:DFFPE
select -assert-count 0 t:DFFR
select -assert-count 0 t:DFFRE
select -assert-count 2 t:DFFS
select -assert-count 2 t:DFFSE
select -assert-count 12 t:LUT2

# check the expected leftover init values
# this would happen if your reset value is not the initial value
# which would be weird
select -assert-count 8 a:init