yosys/tests/arch/common/adffs.v

52 lines
881 B
Verilog

module adff( input d, clk, clr, output reg q );
`ifndef NO_INIT
initial begin
q = 0;
end
`endif
always @( posedge clk, posedge clr )
if ( clr )
q <= 1'b0;
else
q <= d;
endmodule
module adffn( input d, clk, clr, output reg q );
`ifndef NO_INIT
initial begin
q = 0;
end
`endif
always @( posedge clk, negedge clr )
if ( !clr )
q <= 1'b0;
else
q <= d;
endmodule
module dffs( input d, clk, pre, clr, output reg q );
`ifndef NO_INIT
initial begin
q = 0;
end
`endif
always @( posedge clk )
if ( pre )
q <= 1'b1;
else
q <= d;
endmodule
module ndffnr( input d, clk, pre, clr, output reg q );
`ifndef NO_INIT
initial begin
q = 0;
end
`endif
always @( negedge clk )
if ( !clr )
q <= 1'b0;
else
q <= d;
endmodule