implementing a processor ( mips single cycle )

Question

i have a mini project , in this project i need to implement a MIPS single cycle processor by Verilog. here I write the ALU and ALUControl and FileRegister but i have a problem to implement the Pc ( program counter ) for this ... i want this Pc support branch and jump. I need instructions for supporting branch but i don't know how can access to instruction. please help me to implement InstructionMemory and Pc. here is my code :

module ALU(ALUctl, A, B, ALUOut, Zero);
input [3:0] ALUctl;
input [31:0] A,B;
output reg [31:0] ALUOut;
output Zero;
assign Zero = (ALUOut==0); //Zero is true if ALUOut is 0
always @(ALUctl, A, B) begin //reevaluate if these change
    case (ALUctl)
        0: ALUOut <= A & B;
        1: ALUOut <= A | B;
        2: ALUOut <= A + B;
        6: ALUOut <= A - B;
        7: ALUOut <= A < B ? 1 : 0;
        12: ALUOut <= ~(A | B); // result is nor
        default: ALUOut <= 0;
    endcase
end

endmodule

module ALUControl(ALUOp, FuncCode, ALUCtl);
input [1:0] ALUOp;
input [5:0] FuncCode;
output reg [3:0] ALUCtl;
always @(ALUOp, FuncCode) begin
    if ( ALUOp == 2 )
        case (FuncCode)
            32: ALUCtl<=2; // add
            34: ALUCtl<=6; //subtract
            36: ALUCtl<=0; // and
            37: ALUCtl<=1; // or
            39: ALUCtl<=12; // nor
            42: ALUCtl<=7; // slt
            default: ALUCtl<=15; // should not happen
        endcase
    else
        case (ALUOp)
            0:  ALUCtl<=2;
            1: ALUCtl<=6;
            default: ALUCtl<=15; // should not happen
        endcase
end

endmodule

module RegFile(ra1, rd1 , ra2 , rd2 , clk , RegWrite , wa ,wd );
input[4:0] ra1;
output[31:0] rd1;
input[4:0] ra2;
output[31:0] rd2;
input clk;
input werf ;
input[4:0] wa;
input[31:0] wd;
reg [31:0] registers[31:0];

assign rd1 = registers[ra1];
assign rd2 = registers[ra2];

always@ ( posedge clk )
    if (RegWrite)
        registers[wa] <= wd;

endmodule

Answer 1

here is the code of pc

module PC(clk  , instruction ,  zero , branch , jump , pc );
input clk ;
input[31:0] instruction ;
reg[31:0] npc;
input zero ;
input jump ;
input branch ;
wire[31:0] pcInc;
wire[31:0] Branch1 ;
wire[15:0] address;
wire[31:0] branchAdd;
reg[31:0] mux1; 
wire select1 ;
wire[31:0] jumpAdd ;
output [31:0] pc ;
reg [31:0] pc ;


assign select1 = branch & zero ;
assign pcInc = pc + 4 ;
assign address = instruction[15:0];
assign Branch1 =  {{16{address[15]}},address[15:0]} ;   // sign extension
assign branchAdd = pcInc + ( branch << 2 ) ;

always@( branchAdd or pcInc or select1  ) 
begin
    if ( select1 == 1 )
        mux1 = branchAdd ;
    else
        mux1 = pcInc ;
end

assign jumpAdd = ( instruction[25:0] << 2 );

always@ ( jump or jumpAdd or mux1 )
begin
    if ( jump == 1 ) 
        npc = jumpAdd ;
    else
        npc = mux1;
end

always @(posedge clk )
    pc <= npc;

endmodule