补交11.25

module fulladder (sum, c_out, a, b, c_in);

wire s1, c1, c2;

output sum;

output c_out;

input a, b, c_in;

assign{c_out,sum}=a+b+c_in;

endmodule

module adder3(sum, c_out, a, b, c_in);

wire [2:0] c; 

output [2:0] sum;

output c_out;

input [2:0] a;

input [2:0] b;

input c_in;

fulladder fa1(sum[0], c[1], a[0], b[0], c_in) ;

fulladder fa2(sum[1], c[2], a[1], b[1], c[1]) ;

fulladder fa3(sum[2], c_out, a[2], b[2], c[2]) ;

endmodule

module main;

reg [2:0] a;

reg [2:0] b;

wire [2:0] sum;

wire c_out;

adder3 DUT (sum, c_out, a, b, 1'b0);

initial

begin

  a = 4'b0101;

  b = 4'b0000;

end

always #50 begin

  b=b+1;

  $monitor("%dns monitor: a=%d b=%d sum=%d", $stime, a, b, sum);

end

initial #2000 $finish;

endmodule

补交11.25三位元全加法器

module fulladder (sum, c_out, a, b, c_in);

wire s1, c1, c2;

output sum;

output c_out;

input a, b, c_in;

xor g1(s1, a, b);

xor g2(sum, s1, c_in);

and g3(c1, a,b);

and g4(c2, s1, c_in) ;

xor g5(c_out, c2, c1) ;

endmodule

module adder3(sum, c_out, a, b, c_in);

wire [2:0] c;

output [2:0] sum;

output c_out;

input [2:0] a;

input [2:0] b;

input c_in;

fulladder fa1(sum[0], c[1], a[0], b[0], c_in) ;

fulladder fa2(sum[1], c[2], a[1], b[1], c[1]) ;

fulladder fa3(sum[2], c_out, a[2], b[2], c[2]) ;

endmodule

module main;

reg [2:0] a;

reg [2:0] b;

wire [2:0] sum;

wire c_out;

adder3 DUT (sum, c_out, a, b, 1'b0);

initial

begin

  a = 4'b0101;

  b = 4'b0000;

end

always #50 begin

 b=b+1;

  $monitor("%dns monitor: a=%d b=%d sum=%d", $stime, a, b, sum);

end

initial #2000 $finish;

endmodule

补交11.18(1)

module test_adder1;

 reg a,b;

 reg carry_in ; 

 wire sum;

 wire carry_out;

 adder1_behavorial A1(carry_out, sum, a, b, carry_in);

 initial 

  begin

    carry_in = 0; a = 0; b = 0; 

    # 100 if ( carry_out != 0 | sum !== 0) 

                $display(" 0+0+0=00 sum is WRONG!");

              else

                $display(" 0+0+0=00 sum is RIGHT!");

    carry_in = 0; a = 0; b = 1; 

    # 100 if ( carry_out != 0 | sum !== 1) 

               $display(" 0+0+1=01 sum is WRONG!");

              else

               $display(" 0+0+1=01 sum is RIGHT!");

    carry_in = 0; a = 1; b = 0; 

    # 100 if ( carry_out != 0 | sum !== 1) 

               $display(" 0+1+0=01 sum is WRONG!");

              else

               $display(" 0+1+0=01 sum is RIGHT!");

    carry_in = 0; a = 1; b = 1; 

    # 100 if ( carry_out != 1 | sum !== 0)  

       $display(" 0+1+1=10 sum is WRONG!");

              else

                $display(" 0+1+1=10 sum is RIGHT!");

    carry_in = 1; a = 0; b = 0; 

    # 100 if ( carry_out != 0 | sum !== 1) 

               $display(" 1+0+0=01 sum is WRONG!");

              else

               $display(" 1+0+0=01 sum is RIGHT!");

     carry_in = 1; a = 0; b = 1; 

    # 100 if ( carry_out != 1 | sum !== 0) 

                $display(" 1+0+1=10 sum is WRONG!");

              else

                $display(" 1+0+1=10 sum is RIGHT!");

    carry_in = 1; a = 1; b = 0; 

    # 100 if ( carry_out != 1 | sum !== 0) 

               $display(" 1+1+0=10 sum is WRONG!");

              else

               $display(" 1+1+0=10 sum is RIGHT!");

    carry_in = 1; a = 1; b = 1; 

    # 100 if ( carry_out != 1 | sum !== 1) 

               $display(" 1+1+1=11 sum is WRONG!");

              else

               $display(" 1+1+1=11 sum is RIGHT!");

    $finish;

  end

endmodule

module adder1_behavorial (carry_out, sum, a, b, carry_in);

 input a, b, carry_in;

 output carry_out, sum;

  assign sum = (~a&b&~carry_in)|(~carry_in&a&~b)|(a&b&carry_in)|(~a&~

b&carry_in);

  assign carry_out = a&carry_in|a&b|b&carry_in; 

endmodule

补交11.18日(2)

module top;

wire A, B, Cin, c1, c2, c3, sum, Cout;

system_clock #400 clock1(Cin);

system_clock #200 clock2(A);

system_clock #100 clock3(B);

xor(c1, A, B);

and(c2, A, B);

xor(sum, c1, Cin);

and(c3, c1, Cin);

xor(Cout, c3, Cin);

endmodule

module system_clock(clk);

parameter PERIOD=100;

output clk;

reg clk;

initial clk=0;

always

 begin

#(PERIOD/2) clk=~clk;

 end

always@(posedge clk)

 if($time>1000)$stop;

endmodule