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//
// TV80 8-Bit Microprocessor Core
// Based on the VHDL T80 core by Daniel Wallner (jesus@opencores.org)
//
// Copyright (c) 2004 Guy Hutchison (ghutchis@opencores.org)
//
// Permission is hereby granted, free of charge, to any person obtaining a 
// copy of this software and associated documentation files (the "Software"), 
// to deal in the Software without restriction, including without limitation 
// the rights to use, copy, modify, merge, publish, distribute, sublicense, 
// and/or sell copies of the Software, and to permit persons to whom the 
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included 
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
module tv80_mcode_base
  (/*AUTOARG*/
  // Outputs
  output_vector, 
  // Inputs
  IR, MCycle, F, NMICycle, IntCycle, tstate
  );
 
  parameter             Mode   = 0;
  parameter             Flag_C = 0;
  parameter             Flag_N = 1;
  parameter             Flag_P = 2;
  parameter             Flag_X = 3;
  parameter             Flag_H = 4;
  parameter             Flag_Y = 5;
  parameter             Flag_Z = 6;
  parameter             Flag_S = 7;
 
  output [67:0]         output_vector;
 
  input [7:0]           IR;
  input [6:0]           MCycle                  ;
  input [7:0]           F                       ;
  input                 NMICycle                ;
  input                 IntCycle                ;
  input [6:0]           tstate;
 
  // regs
  reg [2:0]             MCycles                 ;
  reg [2:0]             TStates                 ;
  reg [1:0]             Prefix                  ; // None,BC,ED,DD/FD
  reg                   Inc_PC                  ;
  reg                   Inc_WZ                  ;
  reg [3:0]             IncDec_16               ; // BC,DE,HL,SP   0 is inc
  reg                   Read_To_Reg             ;
  reg                   Read_To_Acc             ;
  reg [3:0]             Set_BusA_To     ; // B,C,D,E,H,L,DI/DB,A,SP(L),SP(M),0,F
  reg [3:0]             Set_BusB_To     ; // B,C,D,E,H,L,DI,A,SP(L),SP(M),1,F,PC(L),PC(M),0
  reg [3:0]             ALU_Op                  ;
  reg                   Save_ALU                ;
  reg                   PreserveC               ;
  reg                   Arith16                 ;
  reg [2:0]             Set_Addr_To             ; // aNone,aXY,aIOA,aSP,aBC,aDE,aZI
  reg                   IORQ                    ;
  reg                   Jump                    ;
  reg                   JumpE                   ;
  reg                   JumpXY                  ;
  reg                   Call                    ;
  reg                   RstP                    ;
  reg                   LDZ                     ;
  reg                   LDW                     ;
  reg                   LDSPHL                  ;
  reg [2:0]             Special_LD              ; // A,I;A,R;I,A;R,A;None
  reg                   ExchangeDH              ;
  reg                   ExchangeRp              ;
  reg                   ExchangeAF              ;
  reg                   ExchangeRS              ;
  reg                   I_DJNZ                  ;
  reg                   I_CPL                   ;
  reg                   I_CCF                   ;
  reg                   I_SCF                   ;
  reg                   I_RETN                  ;
  reg                   I_BT                    ;
  reg                   I_BC                    ;
  reg                   I_BTR                   ;
  reg                   I_RLD                   ;
  reg                   I_RRD                   ;
  reg                   I_INRC                  ;
  reg                   SetDI                   ;
  reg                   SetEI                   ;
  reg [1:0]             IMode                   ;
  reg                   Halt                    ;
  reg                   NoRead                  ;
  reg                   Write   ;                
 
  parameter             aNone   = 3'b111;
  parameter             aBC     = 3'b000;
  parameter             aDE     = 3'b001;
  parameter             aXY     = 3'b010;
  parameter             aIOA    = 3'b100;
  parameter             aSP     = 3'b101;
  parameter             aZI     = 3'b110;
  //    constant aNone  : std_logic_vector[2:0] = 3'b000;
  //    constant aXY    : std_logic_vector[2:0] = 3'b001;
  //    constant aIOA   : std_logic_vector[2:0] = 3'b010;
  //    constant aSP    : std_logic_vector[2:0] = 3'b011;
  //    constant aBC    : std_logic_vector[2:0] = 3'b100;
  //    constant aDE    : std_logic_vector[2:0] = 3'b101;
  //    constant aZI    : std_logic_vector[2:0] = 3'b110;
 
  function is_cc_true;
    input [7:0] F;
    input [2:0] cc;
    begin
      if (Mode == 3 ) 
        begin
          case (cc)
            3'b000  : is_cc_true = F[7] == 1'b0; // NZ
            3'b001  : is_cc_true = F[7] == 1'b1; // Z
            3'b010  : is_cc_true = F[4] == 1'b0; // NC
            3'b011  : is_cc_true = F[4] == 1'b1; // C
            3'b100  : is_cc_true = 0;
            3'b101  : is_cc_true = 0;
            3'b110  : is_cc_true = 0;
            3'b111  : is_cc_true = 0;
          endcase
        end 
      else 
        begin
          case (cc)
            3'b000  : is_cc_true = F[6] == 1'b0; // NZ
            3'b001  : is_cc_true = F[6] == 1'b1; // Z
            3'b010  : is_cc_true = F[0] == 1'b0; // NC
            3'b011  : is_cc_true = F[0] == 1'b1; // C
            3'b100  : is_cc_true = F[2] == 1'b0; // PO
            3'b101  : is_cc_true = F[2] == 1'b1; // PE
            3'b110  : is_cc_true = F[7] == 1'b0; // P
            3'b111  : is_cc_true = F[7] == 1'b1; // M
          endcase
        end
    end
  endfunction // is_cc_true
 
 
  reg [2:0] DDD;
  reg [2:0] SSS;
  reg [1:0] DPAIR;
 
  always @ (/*AUTOSENSE*/F or IR or IntCycle or MCycle or NMICycle
            or tstate)
    begin
      DDD = IR[5:3];
      SSS = IR[2:0];
      DPAIR = IR[5:4];
 
      MCycles = 3'b001;
      if (MCycle[0] ) 
        begin
          TStates = 3'b100;
        end 
      else 
        begin
          TStates = 3'b011;
        end
      Prefix = 2'b00;
      Inc_PC = 1'b0;
      Inc_WZ = 1'b0;
      IncDec_16 = 4'b0000;
      Read_To_Acc = 1'b0;
      Read_To_Reg = 1'b0;
      Set_BusB_To = 4'b0000;
      Set_BusA_To = 4'b0000;
      ALU_Op = { 1'b0, IR[5:3] };
      Save_ALU = 1'b0;
      PreserveC = 1'b0;
      Arith16 = 1'b0;
      IORQ = 1'b0;
      Set_Addr_To = aNone;
      Jump = 1'b0;
      JumpE = 1'b0;
      JumpXY = 1'b0;
      Call = 1'b0;
      RstP = 1'b0;
      LDZ = 1'b0;
      LDW = 1'b0;
      LDSPHL = 1'b0;
      Special_LD = 3'b000;
      ExchangeDH = 1'b0;
      ExchangeRp = 1'b0;
      ExchangeAF = 1'b0;
      ExchangeRS = 1'b0;
      I_DJNZ = 1'b0;
      I_CPL = 1'b0;
      I_CCF = 1'b0;
      I_SCF = 1'b0;
      I_RETN = 1'b0;
      I_BT = 1'b0;
      I_BC = 1'b0;
      I_BTR = 1'b0;
      I_RLD = 1'b0;
      I_RRD = 1'b0;
      I_INRC = 1'b0;
      SetDI = 1'b0;
      SetEI = 1'b0;
      IMode = 2'b11;
      Halt = 1'b0;
      NoRead = 1'b0;
      Write = 1'b0;
 
 
      casex (IR)
        // 8 BIT LOAD GROUP
        8'b01xxxxxx :
          begin
            if (IR[5:0] == 6'b110110)
              Halt = 1'b1;
            else if (IR[2:0] == 3'b110)
              begin
                // LD r,(HL)
                MCycles = 3'b010;
                if (MCycle[0])
                  Set_Addr_To = aXY;
                if (MCycle[1])
                  begin
                    Set_BusA_To[2:0] = DDD;
                    Read_To_Reg = 1'b1;
                  end
              end // if (IR[2:0] == 3'b110)
            else if (IR[5:3] == 3'b110)
              begin
                // LD (HL),r
                MCycles = 3'b010;
                if (MCycle[0])
                  begin
                    Set_Addr_To = aXY;
                    Set_BusB_To[2:0] = SSS;
                    Set_BusB_To[3] = 1'b0;
                  end
                if (MCycle[1])
                  Write = 1'b1;
              end // if (IR[5:3] == 3'b110)
            else
              begin
                Set_BusB_To[2:0] = SSS;
                ExchangeRp = 1'b1;
                Set_BusA_To[2:0] = DDD;
                Read_To_Reg = 1'b1;
              end // else: !if(IR[5:3] == 3'b110)
          end // case: 8'b01xxxxxx                                    
 
        8'b00xxx110 :
          begin
            if (IR[5:3] == 3'b110)
              begin
                // LD (HL),n
                MCycles = 3'b011;
                if (MCycle[1])
                  begin
                    Inc_PC = 1'b1;
                    Set_Addr_To = aXY;
                    Set_BusB_To[2:0] = SSS;
                    Set_BusB_To[3] = 1'b0;
                  end
                if (MCycle[2])
                  Write = 1'b1;
              end // if (IR[5:3] == 3'b110)
            else
              begin
                // LD r,n
                MCycles = 3'b010;
                if (MCycle[1])
                  begin
                    Inc_PC = 1'b1;
                    Set_BusA_To[2:0] = DDD;
                    Read_To_Reg = 1'b1;
                  end
              end
          end
 
        8'b00001010  :
          begin
            // LD A,(BC)
            MCycles = 3'b010;
            if (MCycle[0])
              Set_Addr_To = aBC;
            if (MCycle[1])
              Read_To_Acc = 1'b1;
          end // case: 8'b00001010
 
        8'b00011010  :
          begin
            // LD A,(DE)
            MCycles = 3'b010;
            if (MCycle[0])
              Set_Addr_To = aDE;
            if (MCycle[1])
              Read_To_Acc = 1'b1;
          end // case: 8'b00011010
 
        8'b00111010  :
          begin
            if (Mode == 3 ) 
              begin
                // LDD A,(HL)
                MCycles = 3'b010;
                if (MCycle[0])
                  Set_Addr_To = aXY;
                if (MCycle[1])
                  begin
                    Read_To_Acc = 1'b1;
                    IncDec_16 = 4'b1110;
                  end
              end 
            else 
              begin
                // LD A,(nn)
                MCycles = 3'b100;
                if (MCycle[1])
                  begin
                    Inc_PC = 1'b1;
                    LDZ = 1'b1;
                  end
                if (MCycle[2])
                  begin
                    Set_Addr_To = aZI;
                    Inc_PC = 1'b1;
                  end
                if (MCycle[3])
                  begin
                    Read_To_Acc = 1'b1;
                  end
              end // else: !if(Mode == 3 )
          end // case: 8'b00111010
 
        8'b00000010  :
          begin
            // LD (BC),A
            MCycles = 3'b010;
            if (MCycle[0])
              begin
                Set_Addr_To = aBC;
                Set_BusB_To = 4'b0111;
              end
            if (MCycle[1])
              begin
                Write = 1'b1;
              end
          end // case: 8'b00000010
 
        8'b00010010  :
          begin
            // LD (DE),A
            MCycles = 3'b010;
            case (1'b1) // MCycle
              MCycle[0] :
                begin
                  Set_Addr_To = aDE;
                  Set_BusB_To = 4'b0111;
                end
              MCycle[1] :
                Write = 1'b1;
              default :;
            endcase // case(MCycle)
          end // case: 8'b00010010
 
        8'b00110010  :
          begin
            if (Mode == 3 ) 
              begin
                // LDD (HL),A
                MCycles = 3'b010;
                case (1'b1) // MCycle
                  MCycle[0] :
                    begin
                      Set_Addr_To = aXY;
                      Set_BusB_To = 4'b0111;
                    end
                  MCycle[1] :
                    begin
                      Write = 1'b1;
                      IncDec_16 = 4'b1110;
                    end
                  default :;
                endcase // case(MCycle)
 
              end 
            else 
              begin
                // LD (nn),A
                MCycles = 3'b100;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      LDZ = 1'b1;
                    end
                  MCycle[2] :
                    begin
                      Set_Addr_To = aZI;
                      Inc_PC = 1'b1;
                      Set_BusB_To = 4'b0111;
                    end
                  MCycle[3] :
                    begin
                      Write = 1'b1;
                    end
                  default :;
                endcase
              end // else: !if(Mode == 3 )
          end // case: 8'b00110010
 
 
        // 16 BIT LOAD GROUP
        8'b00000001,8'b00010001,8'b00100001,8'b00110001  :
          begin
            // LD dd,nn
            MCycles = 3'b011;
            case (1'b1) // MCycle
              MCycle[1] :
                begin
                  Inc_PC = 1'b1;
                  Read_To_Reg = 1'b1;
                  if (DPAIR == 2'b11 ) 
                    begin
                      Set_BusA_To[3:0] = 4'b1000;
                    end 
                  else 
                    begin
                      Set_BusA_To[2:1] = DPAIR;
                      Set_BusA_To[0] = 1'b1;
                    end
                end // case: 2
 
              MCycle[2] :
                begin
                  Inc_PC = 1'b1;
                  Read_To_Reg = 1'b1;
                  if (DPAIR == 2'b11 ) 
                    begin
                      Set_BusA_To[3:0] = 4'b1001;
                    end 
                  else 
                    begin
                      Set_BusA_To[2:1] = DPAIR;
                      Set_BusA_To[0] = 1'b0;
                    end
                end // case: 3
 
              default :;
            endcase // case(MCycle)
          end // case: 8'b00000001,8'b00010001,8'b00100001,8'b00110001
 
        8'b00101010  :
          begin
            if (Mode == 3 ) 
              begin
                // LDI A,(HL)
                MCycles = 3'b010;
                case (1'b1) // MCycle
                  MCycle[0] :
                    Set_Addr_To = aXY;
                  MCycle[1] :
                    begin
                      Read_To_Acc = 1'b1;
                      IncDec_16 = 4'b0110;
                    end
 
                  default :;
                endcase
              end 
            else 
              begin
                // LD HL,(nn)
                MCycles = 3'b101;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      LDZ = 1'b1;
                    end
                  MCycle[2] :
                    begin
                      Set_Addr_To = aZI;
                      Inc_PC = 1'b1;
                      LDW = 1'b1;
                    end
                  MCycle[3] :
                    begin
                      Set_BusA_To[2:0] = 3'b101; // L
                      Read_To_Reg = 1'b1;
                      Inc_WZ = 1'b1;
                      Set_Addr_To = aZI;
                    end
                  MCycle[4] :
                    begin
                      Set_BusA_To[2:0] = 3'b100; // H
                      Read_To_Reg = 1'b1;
                    end
                  default :;
                endcase
              end // else: !if(Mode == 3 )
          end // case: 8'b00101010
 
        8'b00100010  :
          begin
            if (Mode == 3 ) 
              begin
                // LDI (HL),A
                MCycles = 3'b010;
                case (1'b1) // MCycle
                  MCycle[0] :
                    begin
                      Set_Addr_To = aXY;
                      Set_BusB_To = 4'b0111;
                    end
                  MCycle[1] :
                    begin
                      Write = 1'b1;
                      IncDec_16 = 4'b0110;
                    end
                  default :;
                endcase
              end 
            else 
              begin
                // LD (nn),HL
                MCycles = 3'b101;
                case (1'b1) // MCycle                        
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      LDZ = 1'b1;
                    end
 
                  MCycle[2] :
                    begin
                      Set_Addr_To = aZI;
                      Inc_PC = 1'b1;
                      LDW = 1'b1;
                      Set_BusB_To = 4'b0101; // L
                    end
 
                  MCycle[3] :
                    begin
                      Inc_WZ = 1'b1;
                      Set_Addr_To = aZI;
                      Write = 1'b1;
                      Set_BusB_To = 4'b0100; // H
                    end
                  MCycle[4] :                          
                    Write = 1'b1;
                  default :;
                endcase
              end // else: !if(Mode == 3 )
          end // case: 8'b00100010
 
        8'b11111001  :
          begin
            // LD SP,HL
            TStates = 3'b110;
            LDSPHL = 1'b1;
          end
 
        8'b11xx0101 :
          begin
            // PUSH qq
            MCycles = 3'b011;
            case (1'b1) // MCycle                    
              MCycle[0] :
                begin
                  TStates = 3'b101;
                  IncDec_16 = 4'b1111;
                  Set_Addr_To = aSP;
                  if (DPAIR == 2'b11 ) 
                    begin
                      Set_BusB_To = 4'b0111;
                    end 
                  else
                    begin
                      Set_BusB_To[2:1] = DPAIR;
                      Set_BusB_To[0] = 1'b0;
                      Set_BusB_To[3] = 1'b0;
                    end
                end // case: 1
 
              MCycle[1] :
                begin
                  IncDec_16 = 4'b1111;
                  Set_Addr_To = aSP;
                  if (DPAIR == 2'b11 ) 
                    begin
                      Set_BusB_To = 4'b1011;
                    end 
                  else 
                    begin
                      Set_BusB_To[2:1] = DPAIR;
                      Set_BusB_To[0] = 1'b1;
                      Set_BusB_To[3] = 1'b0;
                    end
                  Write = 1'b1;
                end // case: 2
 
              MCycle[2] :
                Write = 1'b1;
              default :;
            endcase // case(MCycle)
          end // case: 8'b11000101,8'b11010101,8'b11100101,8'b11110101
 
        8'b11xx0001 :
          begin
            // POP qq
            MCycles = 3'b011;
            case (1'b1) // MCycle
              MCycle[0] :
                Set_Addr_To = aSP;
              MCycle[1] :
                begin
                  IncDec_16 = 4'b0111;
                  Set_Addr_To = aSP;
                  Read_To_Reg = 1'b1;
                  if (DPAIR == 2'b11 ) 
                    begin
                      Set_BusA_To[3:0] = 4'b1011;
                    end 
                  else 
                    begin
                      Set_BusA_To[2:1] = DPAIR;
                      Set_BusA_To[0] = 1'b1;
                    end
                end // case: 2
 
              MCycle[2] :
                begin
                  IncDec_16 = 4'b0111;
                  Read_To_Reg = 1'b1;
                  if (DPAIR == 2'b11 ) 
                    begin
                      Set_BusA_To[3:0] = 4'b0111;
                    end 
                  else 
                    begin
                      Set_BusA_To[2:1] = DPAIR;
                      Set_BusA_To[0] = 1'b0;
                    end
                end // case: 3
 
              default :;
            endcase // case(MCycle)
          end // case: 8'b11000001,8'b11010001,8'b11100001,8'b11110001
 
 
        // EXCHANGE, BLOCK TRANSFER AND SEARCH GROUP
        8'b11101011  :
          begin
            if (Mode != 3 ) 
              begin
                // EX DE,HL
 
                case (1'b1)
                  tstate[3] :
                    begin
                      Set_BusA_To = 4'b0100;
                      Set_BusB_To = 4'b0010;
                      ExchangeDH = 1'b1;
                    end
 
                  tstate[4] :
                    begin
                      Set_BusA_To = 4'b0010;
                      ExchangeDH = 1'b1;
                    end
 
                  default :;
                endcase
              end
          end
 
        8'b00001000  :
          begin
            if (Mode == 3 ) 
              begin
                // LD (nn),SP
                MCycles = 3'b101;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      LDZ = 1'b1;
                    end
 
                  MCycle[2] :
                    begin
                      Set_Addr_To = aZI;
                      Inc_PC = 1'b1;
                      LDW = 1'b1;
                      Set_BusB_To = 4'b1000;
                    end
 
                  MCycle[3] :
                    begin
                      Inc_WZ = 1'b1;
                      Set_Addr_To = aZI;
                      Write = 1'b1;
                      Set_BusB_To = 4'b1001;
                    end
 
                  MCycle[4] :
                    Write = 1'b1;
                  default :;
                endcase
              end 
            else if (Mode < 2 ) 
              begin
                // EX AF,AF'
                ExchangeAF = 1'b1;
              end
          end // case: 8'b00001000
 
        8'b11011001  :
          begin
            if (Mode == 3 ) 
              begin
                // RETI
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[0] :
                    Set_Addr_To = aSP;
                  MCycle[1] :
                    begin
                      IncDec_16 = 4'b0111;
                      Set_Addr_To = aSP;
                      LDZ = 1'b1;
                    end
 
                  MCycle[2] :
                    begin
                      Jump = 1'b1;
                      IncDec_16 = 4'b0111;
                      I_RETN = 1'b1;
                      SetEI = 1'b1;
                    end
                  default :;
                endcase
              end 
            else if (Mode < 2 ) 
              begin
                // EXX
                ExchangeRS = 1'b1;
              end
          end // case: 8'b11011001
 
        8'b11100011  :
          begin
            if (Mode != 3 ) 
              begin
                // EX (SP),HL
                MCycles = 3'b101;
                case (1'b1) // MCycle
                  MCycle[0] :
                    Set_Addr_To = aSP;
                  MCycle[1] :
                    begin
                      Read_To_Reg = 1'b1;
                      Set_BusA_To = 4'b0101;
                      Set_BusB_To = 4'b0101;
                      Set_Addr_To = aSP;
                    end
                  MCycle[2] :
                    begin
                      IncDec_16 = 4'b0111;
                      Set_Addr_To = aSP;
                      TStates = 3'b100;
                      Write = 1'b1;
                    end
                  MCycle[3] :
                    begin
                      Read_To_Reg = 1'b1;
                      Set_BusA_To = 4'b0100;
                      Set_BusB_To = 4'b0100;
                      Set_Addr_To = aSP;
                    end
                  MCycle[4] :
                    begin
                      IncDec_16 = 4'b1111;
                      TStates = 3'b101;
                      Write = 1'b1;
                    end
 
                  default :;
                endcase
              end // if (Mode != 3 )
          end // case: 8'b11100011
 
 
        // 8 BIT ARITHMETIC AND LOGICAL GROUP
        8'b10xxxxxx :
          begin
            if (IR[2:0] == 3'b110)
              begin
                // ADD A,(HL)
                // ADC A,(HL)
                // SUB A,(HL)
                // SBC A,(HL)
                // AND A,(HL)
                // OR A,(HL)
                // XOR A,(HL)
                // CP A,(HL)
                MCycles = 3'b010;
                case (1'b1) // MCycle
                  MCycle[0] :
                    Set_Addr_To = aXY;
                  MCycle[1] :
                    begin
                      Read_To_Reg = 1'b1;
                      Save_ALU = 1'b1;
                      Set_BusB_To[2:0] = SSS;
                      Set_BusA_To[2:0] = 3'b111;
                    end
 
                  default :;
                endcase // case(MCycle)
              end // if (IR[2:0] == 3'b110)
            else
              begin
                // ADD A,r
                // ADC A,r
                // SUB A,r
                // SBC A,r
                // AND A,r
                // OR A,r
                // XOR A,r
                // CP A,r
                Set_BusB_To[2:0] = SSS;
                Set_BusA_To[2:0] = 3'b111;
                Read_To_Reg = 1'b1;
                Save_ALU = 1'b1;
              end // else: !if(IR[2:0] == 3'b110)                  
          end // case: 8'b10000000,8'b10000001,8'b10000010,8'b10000011,8'b10000100,8'b10000101,8'b10000111,...
 
        8'b11xxx110 :
          begin
            // ADD A,n
            // ADC A,n
            // SUB A,n
            // SBC A,n
            // AND A,n
            // OR A,n
            // XOR A,n
            // CP A,n
            MCycles = 3'b010;
            if (MCycle[1] ) 
              begin
                Inc_PC = 1'b1;
                Read_To_Reg = 1'b1;
                Save_ALU = 1'b1;
                Set_BusB_To[2:0] = SSS;
                Set_BusA_To[2:0] = 3'b111;
              end
          end
 
        8'b00xxx100 :
          begin
            if (IR[5:3] == 3'b110)
              begin
                // INC (HL)
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[0] :
                    Set_Addr_To = aXY;
                  MCycle[1] :
                    begin
                      TStates = 3'b100;
                      Set_Addr_To = aXY;
                      Read_To_Reg = 1'b1;
                      Save_ALU = 1'b1;
                      PreserveC = 1'b1;
                      ALU_Op = 4'b0000;
                      Set_BusB_To = 4'b1010;
                      Set_BusA_To[2:0] = DDD;
                    end // case: 2
 
                  MCycle[2] :
                    Write = 1'b1;
                  default :;
                endcase // case(MCycle)
              end // case: 8'b00110100
            else
              begin
                // INC r
                Set_BusB_To = 4'b1010;
                Set_BusA_To[2:0] = DDD;
                Read_To_Reg = 1'b1;
                Save_ALU = 1'b1;
                PreserveC = 1'b1;
                ALU_Op = 4'b0000;
              end
          end
 
        8'b00xxx101 :
          begin               
            if (IR[5:3] == 3'b110)
              begin
                // DEC (HL)
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[0] :
                    Set_Addr_To = aXY;
                  MCycle[1] :
                    begin
                      TStates = 3'b100;
                      Set_Addr_To = aXY;
                      ALU_Op = 4'b0010;
                      Read_To_Reg = 1'b1;
                      Save_ALU = 1'b1;
                      PreserveC = 1'b1;
                      Set_BusB_To = 4'b1010;
                      Set_BusA_To[2:0] = DDD;
                    end // case: 2
 
                  MCycle[2] :
                    Write = 1'b1;
                  default :;
                endcase // case(MCycle)
              end
            else
              begin
                // DEC r
                Set_BusB_To = 4'b1010;
                Set_BusA_To[2:0] = DDD;
                Read_To_Reg = 1'b1;
                Save_ALU = 1'b1;
                PreserveC = 1'b1;
                ALU_Op = 4'b0010;
              end
          end
 
        // GENERAL PURPOSE ARITHMETIC AND CPU CONTROL GROUPS
        8'b00100111  :
          begin
            // DAA
            Set_BusA_To[2:0] = 3'b111;
            Read_To_Reg = 1'b1;
            ALU_Op = 4'b1100;
            Save_ALU = 1'b1;
          end
 
        8'b00101111  :
          // CPL
          I_CPL = 1'b1;
 
        8'b00111111  :
          // CCF
          I_CCF = 1'b1;
 
        8'b00110111  :
          // SCF
          I_SCF = 1'b1;
 
        8'b00000000  :
          begin
            if (NMICycle == 1'b1 ) 
              begin
                // NMI
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[0] :
                    begin
                      TStates = 3'b101;
                      IncDec_16 = 4'b1111;
                      Set_Addr_To = aSP;
                      Set_BusB_To = 4'b1101;
                    end
 
                  MCycle[1] :
                    begin
                      TStates = 3'b100;
                      Write = 1'b1;
                      IncDec_16 = 4'b1111;
                      Set_Addr_To = aSP;
                      Set_BusB_To = 4'b1100;
                    end
 
                  MCycle[2] :
                    begin
                      TStates = 3'b100;
                      Write = 1'b1;
                    end
 
                  default :;
                endcase // case(MCycle)
 
              end 
            else if (IntCycle == 1'b1 ) 
              begin
                // INT (IM 2)
                MCycles = 3'b101;
                case (1'b1) // MCycle
                  MCycle[0] :
                    begin
                      LDZ = 1'b1;
                      TStates = 3'b101;
                      IncDec_16 = 4'b1111;
                      Set_Addr_To = aSP;
                      Set_BusB_To = 4'b1101;
                    end
 
                  MCycle[1] :
                    begin
                      TStates = 3'b100;
                      Write = 1'b1;
                      IncDec_16 = 4'b1111;
                      Set_Addr_To = aSP;
                      Set_BusB_To = 4'b1100;
                    end
 
                  MCycle[2] :
                    begin
                      TStates = 3'b100;
                      Write = 1'b1;
                    end
 
                  MCycle[3] :
                    begin
                      Inc_PC = 1'b1;
                      LDZ = 1'b1;
                    end
 
                  MCycle[4] :
                    Jump = 1'b1;
                  default :;
                endcase
              end
          end // case: 8'b00000000
 
        8'b11110011  :
          // DI
          SetDI = 1'b1;
 
        8'b11111011  :
          // EI
          SetEI = 1'b1;
 
        // 16 BIT ARITHMETIC GROUP
        8'b00001001,8'b00011001,8'b00101001,8'b00111001  :
          begin
            // ADD HL,ss
            MCycles = 3'b011;
            case (1'b1) // MCycle
              MCycle[1] :
                begin
                  NoRead = 1'b1;
                  ALU_Op = 4'b0000;
                  Read_To_Reg = 1'b1;
                  Save_ALU = 1'b1;
                  Set_BusA_To[2:0] = 3'b101;
                  case (IR[5:4])
                    0,1,2  :
                      begin
                        Set_BusB_To[2:1] = IR[5:4];
                        Set_BusB_To[0] = 1'b1;
                      end
 
                    default :
                      Set_BusB_To = 4'b1000;
                  endcase // case(IR[5:4])
 
                  TStates = 3'b100;
                  Arith16 = 1'b1;
                end // case: 2
 
              MCycle[2] :
                begin
                  NoRead = 1'b1;
                  Read_To_Reg = 1'b1;
                  Save_ALU = 1'b1;
                  ALU_Op = 4'b0001;
                  Set_BusA_To[2:0] = 3'b100;
                  case (IR[5:4])
                    0,1,2  :
                      Set_BusB_To[2:1] = IR[5:4];
                    default :
                      Set_BusB_To = 4'b1001;
                  endcase
                  Arith16 = 1'b1;
                end // case: 3
 
              default :;
            endcase // case(MCycle)
          end // case: 8'b00001001,8'b00011001,8'b00101001,8'b00111001              
 
        8'b00000011,8'b00010011,8'b00100011,8'b00110011  :
          begin
            // INC ss
            TStates = 3'b110;
            IncDec_16[3:2] = 2'b01;
            IncDec_16[1:0] = DPAIR;
          end
 
        8'b00001011,8'b00011011,8'b00101011,8'b00111011  :
          begin
            // DEC ss
            TStates = 3'b110;
            IncDec_16[3:2] = 2'b11;
            IncDec_16[1:0] = DPAIR;
          end
 
        // ROTATE AND SHIFT GROUP
        8'b00000111,
            // RLCA
            8'b00010111,
            // RLA
            8'b00001111,
            // RRCA
            8'b00011111 :
              // RRA
              begin
                Set_BusA_To[2:0] = 3'b111;
                ALU_Op = 4'b1000;
                Read_To_Reg = 1'b1;
                Save_ALU = 1'b1;
              end // case: 8'b00000111,...
 
 
        // JUMP GROUP
        8'b11000011  :
          begin
            // JP nn
            MCycles = 3'b011;
            if (MCycle[1])
              begin
                Inc_PC = 1'b1;
                LDZ = 1'b1;
              end
 
            if (MCycle[2])
              begin
                Inc_PC = 1'b1;
                Jump = 1'b1;
              end
 
          end // case: 8'b11000011
 
        8'b11000010,8'b11001010,8'b11010010,8'b11011010,8'b11100010,8'b11101010,8'b11110010,8'b11111010  :
          begin
            if (IR[5] == 1'b1 && Mode == 3 ) 
              begin
                case (IR[4:3])
                  2'b00  :
                    begin
                      // LD ($FF00+C),A
                      MCycles = 3'b010;
                      case (1'b1) // MCycle
                        MCycle[0] :
                          begin
                            Set_Addr_To = aBC;
                            Set_BusB_To   = 4'b0111;
                          end
                        MCycle[1] :
                          begin
                            Write = 1'b1;
                            IORQ = 1'b1;
                          end
 
                        default :;
                      endcase // case(MCycle)
                    end // case: 2'b00
 
                  2'b01  :
                    begin
                      // LD (nn),A
                      MCycles = 3'b100;
                      case (1'b1) // MCycle
                        MCycle[1] :
                          begin
                            Inc_PC = 1'b1;
                            LDZ = 1'b1;
                          end
 
                        MCycle[2] :
                          begin
                            Set_Addr_To = aZI;
                            Inc_PC = 1'b1;
                            Set_BusB_To = 4'b0111;
                          end
 
                        MCycle[3] :
                          Write = 1'b1;
                        default :;
                      endcase // case(MCycle)
                    end // case: default :...
 
                  2'b10  :
                    begin
                      // LD A,($FF00+C)
                      MCycles = 3'b010;
                      case (1'b1) // MCycle
                        MCycle[0] :
                          Set_Addr_To = aBC;
                        MCycle[1] :
                          begin
                            Read_To_Acc = 1'b1;
                            IORQ = 1'b1;
                          end
                        default :;
                      endcase // case(MCycle)
                    end // case: 2'b10
 
                  2'b11  :
                    begin
                      // LD A,(nn)
                      MCycles = 3'b100;
                      case (1'b1) // MCycle
                        MCycle[1] :
                          begin
                            Inc_PC = 1'b1;
                            LDZ = 1'b1;
                          end
                        MCycle[2] :
                          begin
                            Set_Addr_To = aZI;
                            Inc_PC = 1'b1;
                          end
                        MCycle[3] :
                          Read_To_Acc = 1'b1;
                        default :;
                      endcase // case(MCycle)
                    end
                endcase
              end 
            else 
              begin
                // JP cc,nn
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      LDZ = 1'b1;
                    end
                  MCycle[2] :
                    begin
                      Inc_PC = 1'b1;
                      if (is_cc_true(F, IR[5:3]) ) 
                        begin
                          Jump = 1'b1;
                        end
                    end
 
                  default :;
                endcase
              end // else: !if(DPAIR == 2'b11 )
          end // case: 8'b11000010,8'b11001010,8'b11010010,8'b11011010,8'b11100010,8'b11101010,8'b11110010,8'b11111010
 
        8'b00011000  :
          begin
            if (Mode != 2 ) 
              begin
                // JR e
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[1] :
                    Inc_PC = 1'b1;
                  MCycle[2] :
                    begin
                      NoRead = 1'b1;
                      JumpE = 1'b1;
                      TStates = 3'b101;
                    end
                  default :;
                endcase
              end // if (Mode != 2 )
          end // case: 8'b00011000
 
        8'b00111000  :
          begin
            if (Mode != 2 ) 
              begin
                // JR C,e
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      if (F[Flag_C] == 1'b0 ) 
                        begin
                          MCycles = 3'b010;
                        end
                    end
 
                  MCycle[2] :
                    begin
                      NoRead = 1'b1;
                      JumpE = 1'b1;
                      TStates = 3'b101;
                    end
                  default :;
                endcase
              end // if (Mode != 2 )
          end // case: 8'b00111000
 
        8'b00110000  :
          begin
            if (Mode != 2 ) 
              begin
                // JR NC,e
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      if (F[Flag_C] == 1'b1 ) 
                        begin
                          MCycles = 3'b010;
                        end
                    end
 
                  MCycle[2] :
                    begin
                      NoRead = 1'b1;
                      JumpE = 1'b1;
                      TStates = 3'b101;
                    end
                  default :;
                endcase
              end // if (Mode != 2 )
          end // case: 8'b00110000
 
        8'b00101000  :
          begin
            if (Mode != 2 ) 
              begin
                // JR Z,e
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      if (F[Flag_Z] == 1'b0 ) 
                        begin
                          MCycles = 3'b010;
                        end
                    end
 
                  MCycle[2] :
                    begin
                      NoRead = 1'b1;
                      JumpE = 1'b1;
                      TStates = 3'b101;
                    end
 
                  default :;
                endcase
              end // if (Mode != 2 )
          end // case: 8'b00101000
 
        8'b00100000  :
          begin
            if (Mode != 2 ) 
              begin
                // JR NZ,e
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      if (F[Flag_Z] == 1'b1 ) 
                        begin
                          MCycles = 3'b010;
                        end
                    end
                  MCycle[2] :
                    begin                            
                      NoRead = 1'b1;
                      JumpE = 1'b1;
                      TStates = 3'b101;
                    end
                  default :;
                endcase
              end // if (Mode != 2 )
          end // case: 8'b00100000
 
        8'b11101001  :
          // JP (HL)
          JumpXY = 1'b1;
 
        8'b00010000  :
          begin
            if (Mode == 3 ) 
              begin
                I_DJNZ = 1'b1;
              end 
            else if (Mode < 2 ) 
              begin
                // DJNZ,e
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[0] :
                    begin
                      TStates = 3'b101;
                      I_DJNZ = 1'b1;
                      Set_BusB_To = 4'b1010;
                      Set_BusA_To[2:0] = 3'b000;
                      Read_To_Reg = 1'b1;
                      Save_ALU = 1'b1;
                      ALU_Op = 4'b0010;
                    end
                  MCycle[1] :
                    begin
                      I_DJNZ = 1'b1;
                      Inc_PC = 1'b1;
                    end
                  MCycle[2] :
                    begin
                      NoRead = 1'b1;
                      JumpE = 1'b1;
                      TStates = 3'b101;
                    end
                  default :;
                endcase
              end // if (Mode < 2 )
          end // case: 8'b00010000
 
 
        // CALL AND RETURN GROUP
        8'b11001101  :
          begin
            // CALL nn
            MCycles = 3'b101;
            case (1'b1) // MCycle
              MCycle[1] :
                begin
                  Inc_PC = 1'b1;
                  LDZ = 1'b1;
                end
              MCycle[2] :
                begin
                  IncDec_16 = 4'b1111;
                  Inc_PC = 1'b1;
                  TStates = 3'b100;
                  Set_Addr_To = aSP;
                  LDW = 1'b1;
                  Set_BusB_To = 4'b1101;
                end
              MCycle[3] :
                begin
                  Write = 1'b1;
                  IncDec_16 = 4'b1111;
                  Set_Addr_To = aSP;
                  Set_BusB_To = 4'b1100;
                end
              MCycle[4] :
                begin
                  Write = 1'b1;
                  Call = 1'b1;
                end
              default :;
            endcase // case(MCycle)
          end // case: 8'b11001101
 
        8'b11000100,8'b11001100,8'b11010100,8'b11011100,8'b11100100,8'b11101100,8'b11110100,8'b11111100  :
          begin
            if (IR[5] == 1'b0 || Mode != 3 ) 
              begin
                // CALL cc,nn
                MCycles = 3'b101;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      LDZ = 1'b1;
                    end
                  MCycle[2] :
                    begin
                      Inc_PC = 1'b1;
                      LDW = 1'b1;
                      if (is_cc_true(F, IR[5:3]) ) 
                        begin
                          IncDec_16 = 4'b1111;
                          Set_Addr_To = aSP;
                          TStates = 3'b100;
                          Set_BusB_To = 4'b1101;
                        end 
                      else 
                        begin
                          MCycles = 3'b011;
                        end // else: !if(is_cc_true(F, IR[5:3]) )
                    end // case: 3
 
                  MCycle[3] :
                    begin
                      Write = 1'b1;
                      IncDec_16 = 4'b1111;
                      Set_Addr_To = aSP;
                      Set_BusB_To = 4'b1100;
                    end
 
                  MCycle[4] :
                    begin
                      Write = 1'b1;
                      Call = 1'b1;
                    end
 
                  default :;
                endcase
              end // if (IR[5] == 1'b0 || Mode != 3 )
          end // case: 8'b11000100,8'b11001100,8'b11010100,8'b11011100,8'b11100100,8'b11101100,8'b11110100,8'b11111100
 
        8'b11001001  :
          begin
            // RET
            MCycles = 3'b011;
            case (1'b1) // MCycle
              MCycle[0] :
                begin
                  TStates = 3'b101;
                  Set_Addr_To = aSP;
                end
 
              MCycle[1] :
                begin
                  IncDec_16 = 4'b0111;
                  Set_Addr_To = aSP;
                  LDZ = 1'b1;
                end
 
              MCycle[2] :
                begin
                  Jump = 1'b1;
                  IncDec_16 = 4'b0111;
                end
 
              default :;
            endcase // case(MCycle)
          end // case: 8'b11001001
 
        8'b11000000,8'b11001000,8'b11010000,8'b11011000,8'b11100000,8'b11101000,8'b11110000,8'b11111000  :
          begin                  
            if (IR[5] == 1'b1 && Mode == 3 ) 
              begin
                case (IR[4:3])
                  2'b00  :
                    begin
                      // LD ($FF00+nn),A
                      MCycles = 3'b011;
                      case (1'b1) // MCycle
                        MCycle[1] :
                          begin
                            Inc_PC = 1'b1;
                            Set_Addr_To = aIOA;
                            Set_BusB_To   = 4'b0111;
                          end
 
                        MCycle[2] :
                          Write = 1'b1;
                        default :;
                      endcase // case(MCycle)
                    end // case: 2'b00
 
                  2'b01  :
                    begin
                      // ADD SP,n
                      MCycles = 3'b011;
                      case (1'b1) // MCycle
                        MCycle[1] :
                          begin
                            ALU_Op = 4'b0000;
                            Inc_PC = 1'b1;
                            Read_To_Reg = 1'b1;
                            Save_ALU = 1'b1;
                            Set_BusA_To = 4'b1000;
                            Set_BusB_To = 4'b0110;
                          end
 
                        MCycle[2] :
                          begin
                            NoRead = 1'b1;
                            Read_To_Reg = 1'b1;
                            Save_ALU = 1'b1;
                            ALU_Op = 4'b0001;
                            Set_BusA_To = 4'b1001;
                            Set_BusB_To = 4'b1110;        // Incorrect unsigned !!!!!!!!!!!!!!!!!!!!!
                          end
 
                        default :;
                      endcase // case(MCycle)
                    end // case: 2'b01
 
                  2'b10  :
                    begin
                      // LD A,($FF00+nn)
                      MCycles = 3'b011;
                      case (1'b1) // MCycle
                        MCycle[1] :
                          begin
                            Inc_PC = 1'b1;
                            Set_Addr_To = aIOA;
                          end
 
                        MCycle[2] :
                          Read_To_Acc = 1'b1;
                        default :;
                      endcase // case(MCycle)
                    end // case: 2'b10
 
                  2'b11  :
                    begin
                      // LD HL,SP+n       -- Not correct !!!!!!!!!!!!!!!!!!!
                      MCycles = 3'b101;
                      case (1'b1) // MCycle
                        MCycle[1] :
                          begin
                            Inc_PC = 1'b1;
                            LDZ = 1'b1;
                          end
 
                        MCycle[2] :
                          begin
                            Set_Addr_To = aZI;
                            Inc_PC = 1'b1;
                            LDW = 1'b1;
                          end
 
                        MCycle[3] :
                          begin
                            Set_BusA_To[2:0] = 3'b101; // L
                            Read_To_Reg = 1'b1;
                            Inc_WZ = 1'b1;
                            Set_Addr_To = aZI;
                          end
 
                        MCycle[4] :
                          begin
                            Set_BusA_To[2:0] = 3'b100; // H
                            Read_To_Reg = 1'b1;
                          end
 
                        default :;
                      endcase // case(MCycle)
                    end // case: 2'b11
 
                endcase // case(IR[4:3])
 
              end 
            else 
              begin
                // RET cc
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[0] :
                    begin
                      if (is_cc_true(F, IR[5:3]) )                              
                        begin
                          Set_Addr_To = aSP;
                        end 
                      else 
                        begin
                          MCycles = 3'b001;
                        end
                      TStates = 3'b101;
                    end // case: 1
 
                  MCycle[1] :
                    begin
                      IncDec_16 = 4'b0111;
                      Set_Addr_To = aSP;
                      LDZ = 1'b1;
                    end
                  MCycle[2] :
                    begin
                      Jump = 1'b1;
                      IncDec_16 = 4'b0111;
                    end
                  default :;
                endcase
              end // else: !if(IR[5] == 1'b1 && Mode == 3 )
          end // case: 8'b11000000,8'b11001000,8'b11010000,8'b11011000,8'b11100000,8'b11101000,8'b11110000,8'b11111000
 
        8'b11000111,8'b11001111,8'b11010111,8'b11011111,8'b11100111,8'b11101111,8'b11110111,8'b11111111  :
          begin
            // RST p
            MCycles = 3'b011;
            case (1'b1) // MCycle
              MCycle[0] :
                begin
                  TStates = 3'b101;
                  IncDec_16 = 4'b1111;
                  Set_Addr_To = aSP;
                  Set_BusB_To = 4'b1101;
                end
 
              MCycle[1] :
                begin
                  Write = 1'b1;
                  IncDec_16 = 4'b1111;
                  Set_Addr_To = aSP;
                  Set_BusB_To = 4'b1100;
                end
 
              MCycle[2] :
                begin
                  Write = 1'b1;
                  RstP = 1'b1;
                end
 
              default :;
            endcase // case(MCycle)
          end // case: 8'b11000111,8'b11001111,8'b11010111,8'b11011111,8'b11100111,8'b11101111,8'b11110111,8'b11111111
 
        // INPUT AND OUTPUT GROUP
        8'b11011011  :
          begin
            if (Mode != 3 ) 
              begin
                // IN A,(n)
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      Set_Addr_To = aIOA;
                    end
 
                  MCycle[2] :
                    begin
                      Read_To_Acc = 1'b1;
                      IORQ = 1'b1;
                    end
 
                  default :;
                endcase
              end // if (Mode != 3 )
          end // case: 8'b11011011
 
        8'b11010011  :
          begin
            if (Mode != 3 ) 
              begin
                // OUT (n),A
                MCycles = 3'b011;
                case (1'b1) // MCycle
                  MCycle[1] :
                    begin
                      Inc_PC = 1'b1;
                      Set_Addr_To = aIOA;
                      Set_BusB_To = 4'b0111;
                    end
 
                  MCycle[2] :
                    begin
                      Write = 1'b1;
                      IORQ = 1'b1;
                    end
 
                  default :;
                endcase
              end // if (Mode != 3 )
          end // case: 8'b11010011
 
 
        //----------------------------------------------------------------------------
        //----------------------------------------------------------------------------
        // MULTIBYTE INSTRUCTIONS
        //----------------------------------------------------------------------------
        //----------------------------------------------------------------------------
 
        8'b11001011  :
          begin
            if (Mode != 2 ) 
              begin
                Prefix = 2'b01;
              end
          end              
 
        8'b11101101  :
          begin
            if (Mode < 2 ) 
              begin
                Prefix = 2'b10;
              end
          end
 
        8'b11011101,8'b11111101  :
          begin
            if (Mode < 2 ) 
              begin
                Prefix = 2'b11;
              end
          end
 
      endcase // case(IR)
 
 
    end // always @ (IR, ISet, MCycle, F, NMICycle, IntCycle)
 
  assign output_vector = { MCycles,
                           TStates,   
                           Prefix,   
                           Inc_PC,    
                           Inc_WZ,    
                           IncDec_16,
                           Read_To_Reg,
                           Read_To_Acc,
                           Set_BusA_To,
                           Set_BusB_To,
                           ALU_Op,     
                           Save_ALU,   
                           PreserveC,  
                           Arith16,    
                           Set_Addr_To,
                           IORQ,       
                           Jump,       
                           JumpE,      
                           JumpXY,     
                           Call,       
                           RstP,       
                           LDZ,        
                           LDW,        
                           LDSPHL,     
                           Special_LD, 
                           ExchangeDH, 
                           ExchangeRp, 
                           ExchangeAF, 
                           ExchangeRS, 
                           I_DJNZ,     
                           I_CPL,      
                           I_CCF,      
                           I_SCF,      
                           I_RETN,     
                           I_BT,       
                           I_BC,       
                           I_BTR,      
                           I_RLD,      
                           I_RRD,      
                           I_INRC,     
                           SetDI,      
                           SetEI,      
                           IMode,      
                           Halt,       
                           NoRead,     
                           Write }; 
 
 
  // synopsys dc_script_begin
  // set_attribute current_design "revision" "$Id: tv80_mcode_base.v,v 1.1.2.2 2004-12-16 00:46:34 ghutchis Exp $" -type string -quiet
  // synopsys dc_script_end
endmodule // T80_MCode