please faster

Write a verilog code to swap contents of two registers with register. Your answer: reg temp : always@ (posedge clock) begin temp=b; b=a; temp=a; end reg temp; always (posedge clock) begin temp=b; b=a : a=temp; end reg temp; always @ (posedge clock) begin temp=b; b=a; end reg temp; always @ (posedge clock) begin temp=b; b=a; a= temp