CONTROL UNIT

//Main module for control unit

module control(op,clk,rst,s,d,sd,alucon,decode);

input [9:0]op;

input clk;

output [2:0]s,d;

output [5:0]decode;

output [3:0]alucon;

output rst,sd;

reg [3:0]in;

reg [5:0]decode;

reg [9:0]r;

reg [3:0]alucon;

reg[2:0]s,d;

reg rst,sd;

initial

begin

decode=6'b100000;

end

always@(posedge clk)

begin

if(decode==6'b100000)

begin

in=op[9:6];

s=op[2:0];

r=op;

decode={1'b0,decode[5:1]};

case(in)

0 : begin//clr

rst=1'b1;

sd=1'b1;

d=3'b000;

alucon=4'b0000;

end

1 : begin//mov

rst=1'b0;

sd=1'b1;

d=op[5:3];

alucon=4'b0000;

end

2 : begin//add operation

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b0001;

end

3 : begin//subtraction operation

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b0010;

end

4 : begin//multiplication operation

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b0011;

end

5 : begin//division operation

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b0100;

end

6 : begin//and operation

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b0101;

end

7 : begin//or operation

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b0110;

end

8 : begin//xor operation

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b0111;

end

9 : begin//left shfit

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b1000;

end

10 : begin//right shift

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b1001;

end

11 : begin//rotate left

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b1010;

end

12 : begin//rotate right

rst=1'b0;

sd=1'b0;

d=3'b001;

alucon=4'b1011;

end

default: $display("invalid operation");

endcase

end

else if(decode==6'b0)

begin

if(r==op)

decode=6'b000000;

else

decode=6'b100000;

end

else

decode={1'b0,decode[5:1]};

end

endmodule