addsub2.v

64位乘法器源码verilog,经过验证测试

module addsub2(p,y,cin,op_y,op_c,s,cout);
    input [8:0] p;
    input [8:0] y;
    input cin;
    input op_y;
    input op_c;
    output [8:0] s;
    output cout;

    reg [8:0] s_tmp;
	 reg cout_tmp;

	 always @*
	   case ({op_y, op_c})
		 2'b00:   {cout_tmp, s_tmp} = p + y + cin;
       2'b01:   {cout_tmp, s_tmp} = p + y - cin;
       2'b10:   {cout_tmp, s_tmp} = p - y + cin;
       2'b11:   {cout_tmp, s_tmp} = p - y - cin;
		endcase

	  assign s = s_tmp;
	  assign cout = cout_tmp;
endmodule