module CtrlUnit(input [31:0] instr,input [31:0] rdata1, rdata2,input [31:0] pc,ram_data,hi,lo,alu_r,cop_data,mul_out,input [31:0] exc_addr,input clk,output mtc0,eret,teq_exc,output reg [2:0] mdu,output reg reg_wena,output ram_wena,output reg [3:0] cause,output [4:0] rs,rt,rd,waddr,output reg [31:0] wdata,reg_data,output [31:0] ram_addr,output reg [31:0] pc_in,output reg [31:0] alu_a,alu_b,output reg [3:0] alu_op);//******MIPS-55*********//
    parameter   //SPECIAL OP LIST   5-0ADDU    =   6'b100001,SUBU    =   6'b100011,ADD     =   6'b100000,SUB     =   6'b100010,AND     =   6'b100100,OR      =   6'b100101,XOR     =   6'b100110,NOR     =   6'b100111,SLT     =   6'b101010,SLTU    =   6'b101011,SRL     =   6'b000010,SRA     =   6'b000011,SLL     =   6'b000000,SLLV    =   6'b000100,SRLV    =   6'b000110,SRAV    =   6'b000111,JR      =   6'b001000,JALR    =   6'b001001,MULT    =    6'b011000,MULTU   =   6'b011001,DIV     =   6'b011010,DIVU    =   6'b011011,MFHI    =   6'b010000,MFLO    =   6'b010010,MTHI    =   6'b010001,MTLO    =   6'b010011,BREAK   =   6'b001101,SYSCALL =   6'b001100,TEQ     =   6'b110100,//SPECIAL 2 funcCLZ        =   6'b100000,MUL        =   6'b000010,//REGIMM OP LIST 20-16BLTZ    =   5'b00000,BGEZ    =   5'b00001,//COP0 OP LIST ERET    =   6'b011000,  //5-0&&25TH=1MFC0    =   5'b00000,   //20-16MTC0    =   5'b00100,//OPCODE FIELD  31-26ADDI    =   6'b001000,ADDIU   =   6'b001001,ANDI    =   6'b001100,ORI     =   6'b001101,XORI    =   6'b001110,LW      =   6'b100011,SW      =   6'b101011,BEQ     =   6'b000100,BNE     =   6'b000101,BLEZ    =   6'b000110,BGTZ    =   6'b000111,SLTI    =   6'b001010,SLTIU   =   6'b001011,LUI     =   6'b001111,J       =   6'b000010,JAL     =   6'b000011,LB      =   6'b100000,//    Load Byte Function=6'h24    LBU     =   6'b100100,//    1Load Byte Unsigned LH      =   6'b100001,//    Load high LHU     =   6'b100101,//    Load High UnsignedSB      =   6'b101000,//    Send ByteSH      =   6'b101001,//    Send High
                SPECIAL =   6'b000000,SPECIAL2=    6'b011100,REGIMM  =   6'b000001,COP0    =   6'b010000;  //ALU OPCODE                parameter   _ADDU   =   4'b0000;    //r=a+b unsignedparameter   _ADD    =   4'b0010;    //r=a+b signedparameter   _SUBU   =   4'b0001;    //r=a-b unsignedparameter   _SUB    =   4'b0011;    //r=a-b signedparameter   _AND    =   4'b0100;    //r=a&bparameter   _OR     =   4'b0101;    //r=a|bparameter   _XOR    =   4'b0110;    //r=a^bparameter   _NOR    =   4'b0111;    //r=~(a|b)parameter   _LUI    =   4'b1000;    //r={b[15:0],16'b0}parameter   _SLT    =   4'b1011;    //r=(a-b<0)?1:0 signedparameter   _SLTU   =   4'b1010;    //r=(a-b<0)?1:0 unsignedparameter   _SRA    =   4'b1100;    //r=b>>>a parameter   _SLL    =   4'b1110;    //r=b<<aparameter   _SRL    =   4'b1101;    //r=b>>aparameter    _SYSCALL=   4'b1000,_BREAK    =   4'b1001,_TEQ    =   4'b1101;wire [5:0]  op        =  instr[31:26];assign         rs        =  instr[25:21];assign         rt        =  instr[20:16];assign        rd        =  instr[15:11];wire [5:0]  func    =  instr[5:0];wire [4:0]  shamt   =  instr[10:6];wire [15:0] imm     =  instr[15:0];wire [25:0] addr    =  instr[25:0];parameter   SIGN    =   1'b1;parameter   UNSIGN  =   1'b0;wire     imm_sign    =   (op==ANDI||op==ORI||op==XORI)?UNSIGN:SIGN;wire [31:0] shamt_ext        =   {27'b0,shamt};wire [31:0] imm_ext            =   imm_sign?{{(16){imm[15]}},imm}:{16'b0,imm};reg  [31:0] load_data,clz_data;assign    waddr    =    (op==SPECIAL||op==SPECIAL2)?    rd:    (op==JAL)    ?5'b11111:rt;always@(*)begincase(op)SB:     reg_data    =   {24'b0,rdata2[7:0]};SH:     reg_data    =   {16'b0,rdata2[15:0]};SW:     reg_data    =   rdata2;default:reg_data    =    rdata2;endcasecase(op)LB:     load_data   =   {{24{ram_data[7]}},ram_data[7:0]};LBU:    load_data   =   {24'b0,ram_data[7:0]};LH:     load_data   =   {{16{ram_data[15]}},ram_data[15:0]};LHU:    load_data   =   {16'b0,ram_data[15:0]};LW:     load_data   =   ram_data;default:load_data   =   ram_data;endcaseif(op==SPECIAL)case(func)SYSCALL:cause    =    _SYSCALL;BREAK:    cause    =    _BREAK;TEQ:    cause    =    _TEQ;default:cause    =    5'b0;endcaseelse             cause    =    5'b0;/*1    mult2    multu3    div    4    divu5    mthi6    mtlo7    mul*/if(op==SPECIAL)case(func)MULT:    mdu        =    3'h1;MULTU:    mdu        =    3'h2;DIV:    mdu        =    3'h3;DIVU:    mdu        =    3'h4;MTHI:    mdu        =    3'h5;MTLO:    mdu        =    3'h6;default:mdu        =    3'h0;endcaseelse             mdu        =    3'h0;endwire [31:0] npc                =   pc+4;wire [31:0] pc_branch        =   npc    +    {{(14){imm[15]}},imm,2'b00};wire [31:0] pc_jmp            =    {npc[31:28],addr,2'b00};assign    ram_addr    =   rdata1  +   imm_ext;assign    eret        =    op==COP0 && func==ERET;wire    mfc0        =    op==COP0 && rs==MFC0;assign    mtc0        =    op==COP0 && rs==MTC0;assign    teq_exc        =    rdata1==rdata2;parameter   ENA     =   1'b1;parameter   DIS     =   1'b0;wire mem_load   =   op==LB || op==LH || op==LBU || op==LHU || op==LW;assign ram_wena =   op==SW || op==SH || op==SB;integer i;    always@(*)begincase(op)SPECIAL: case(func)MULTU,DIV,DIVU,JR,MTHI,MTLO,BREAK,SYSCALL:reg_wena    =   DIS;default:reg_wena    =   ENA;    endcaseCOP0:       reg_wena    =   rs==MFC0?ENA:DIS;SPECIAL2,LB,LBU,LH,LHU,ADDI,ADDIU,ANDI,ORI,XORI,LW,SLTI,SLTIU,LUI,JAL:        reg_wena    =   ENA;            default:    reg_wena    =   DIS;endcasecase(op)SPECIAL:case(func)JALR:    wdata   =   npc;MFHI:   wdata   =   hi;MFLO:   wdata   =   lo;default:wdata   =   alu_r;endcase SPECIAL2:beginif(func==CLZ) casez(rdata1)32'b1???????????????????????????????:   wdata   =       32'h0;32'b01??????????????????????????????:   wdata   =       32'h1;32'b001?????????????????????????????:   wdata   =       32'h2;32'b0001????????????????????????????:   wdata   =       32'h3;32'b00001???????????????????????????:   wdata   =       32'h4;32'b000001??????????????????????????:   wdata   =       32'h5;32'b0000001?????????????????????????:   wdata   =       32'h6;32'b00000001????????????????????????:   wdata   =       32'h7;32'b000000001???????????????????????:   wdata   =       32'h8;32'b0000000001??????????????????????:   wdata   =       32'h9;32'b00000000001?????????????????????:   wdata   =       32'ha;32'b000000000001????????????????????:   wdata   =       32'hb;32'b0000000000001???????????????????:   wdata   =       32'hc;32'b00000000000001??????????????????:   wdata   =       32'hd;32'b000000000000001?????????????????:   wdata   =       32'he;32'b0000000000000001????????????????:   wdata   =       32'hf;32'b00000000000000001???????????????:   wdata   =       32'h10;32'b000000000000000001??????????????:   wdata   =       32'h11;32'b0000000000000000001?????????????:   wdata   =       32'h12;32'b00000000000000000001????????????:   wdata   =       32'h13;32'b000000000000000000001???????????:   wdata   =       32'h14;32'b0000000000000000000001??????????:   wdata   =       32'h15;32'b00000000000000000000001?????????:   wdata   =       32'h16;32'b000000000000000000000001????????:   wdata   =       32'h17;32'b0000000000000000000000001???????:   wdata   =       32'h18;32'b00000000000000000000000001??????:   wdata   =       32'h19;32'b000000000000000000000000001?????:   wdata   =       32'h1a;32'b0000000000000000000000000001????:   wdata   =       32'h1b;32'b00000000000000000000000000001???:   wdata   =       32'h1c;32'b000000000000000000000000000001??:   wdata   =       32'h1d;32'b0000000000000000000000000000001?:   wdata   =       32'h1e;32'b00000000000000000000000000000001:   wdata   =        32'h1f;32'b00000000000000000000000000000000:    wdata   =       32'h20;endcaseelse if(func==MUL)    wdata    =    mul_out;else                wdata   =   alu_r;endJAL:                    wdata   =   npc;LW,LB,LH,LBU,LHU:        wdata   =   load_data;COP0:    if(rs==MFC0)    wdata   =   cop_data;else            wdata   =   alu_r;default:                wdata   =   alu_r;endcase//Below is OKcase(op)SPECIAL: case(func)SLL,SRL,SRA:beginalu_a   =   shamt_ext;alu_b   =   rdata2;enddefault:beginalu_a   =   rdata1;alu_b   =   rdata2;endendcaseADDI,ADDIU,ANDI,ORI,XORI,SLTI,SLTIU,LUI:beginalu_a   =   rdata1;alu_b   =   imm_ext;enddefault:beginalu_a   =   rdata1;alu_b   =   rdata2;endendcase//PC Source     case(op)SPECIAL: case(func)SYSCALL,TEQ,BREAK:  pc_in  =   exc_addr;JALR,JR:     pc_in  =   rdata1;   default:pc_in  =   npc; endcaseCOP0: case(func)ERET:   pc_in  =   exc_addr;default:pc_in  =   npc;endcaseREGIMM: case(rt)BLTZ:if(rdata1[31])pc_in  =   pc_branch;elsepc_in  =   npc;BGEZ:if(!rdata1[31])pc_in  =   pc_branch;elsepc_in  =   npc;default:pc_in  =   npc;endcaseJ,JAL:        pc_in  =   pc_jmp;BEQ:if(rdata1==rdata2)pc_in  =   pc_branch;else    pc_in  =   npc;BNE:if(rdata1!=rdata2)pc_in  =   pc_branch;else    pc_in  =   npc;BLEZ:if(rdata1[31] || rdata1==32'b0)pc_in  =   pc_branch;else    pc_in  =   npc;BGTZ:if(!rdata1[31] && rdata1!=32'b0)pc_in  =   pc_branch;else    pc_in  =   npc;default:    pc_in  =   npc; endcasecase(op)SPECIAL:case(func)ADDU:       alu_op  =   _ADDU;SUBU:       alu_op  =   _SUBU;ADD:        alu_op  =   _ADD;SUB:        alu_op  =   _SUB;AND:        alu_op  =   _AND;OR:         alu_op  =   _OR;XOR:        alu_op  =   _XOR;NOR:        alu_op  =   _NOR;SLT:        alu_op  =   _SLT;SRL:        alu_op  =   _SRL;SLL:        alu_op  =   _SLL;SRA:        alu_op  =   _SRA;SLTU:       alu_op  =   _SLTU;SRLV:       alu_op  =   _SRL;SLLV:       alu_op  =   _SLL;SRAV:       alu_op  =   _SRA;default:    alu_op  =   _ADDU;endcase ORI:            alu_op  =   _OR;XORI:           alu_op  =   _XOR;BEQ:            alu_op  =   _SUBU;BNE:            alu_op  =   _SUBU;ANDI:           alu_op  =   _AND;ADDIU:          alu_op  =   _ADDU;ADDI:           alu_op  =   _ADD;SLTI:           alu_op  =   _SLT;SLTIU:          alu_op  =   _SLTU;LUI:            alu_op  =   _LUI;default:        alu_op  =   _ADDU;endcaseend
endmodule