design/sys/iop/dmu/rtl/dmu_dsn_ccc_dep.v

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//
// OpenSPARC T2 Processor File: dmu_dsn_ccc_dep.v
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module dmu_dsn_ccc_dep
  (
   clk,
   rst_l,

   d2j_csr_ring_in,

   dep2cdp_data,

   dep2fsm_acc_vio,
   dep2fsm_done,
   dep2fsm_valid
   );

// ----------------------------------------------------------------------------
// Parameters
// ----------------------------------------------------------------------------
  parameter     IDLE = 2'b00,
                RDMS = 2'b01,
                RDLS = 2'b10;

// ----------------------------------------------------------------------------
// Ports
// ----------------------------------------------------------------------------
  input                                 clk;
  input                                 rst_l;

  input  [`FIRE_CSR_RING_BITS]          d2j_csr_ring_in;

  output [`FIRE_CSR_DATA_BITS]          dep2cdp_data;

  output                                dep2fsm_acc_vio;
  output                                dep2fsm_done;
  output                                dep2fsm_valid;

// ----------------------------------------------------------------------------
// Variables
// ----------------------------------------------------------------------------
  wire [`FIRE_CSR_DATA_BITS]            dep2cdp_data;
  reg                                   dep2fsm_acc_vio, nxt_vio;
  reg                                   dep2fsm_done, nxt_dne;
  reg                                   dep2fsm_valid, nxt_vld;

  reg [`FIRE_CSR_CMND_BITS]             cmnd;
  reg [`FIRE_CSR_DATA_BITS]             data;
  reg [1:0]                             state, nxt_state;
  reg [1:0]                             data_ld;
  reg                                   cmnd_ld;

// ----------------------------------------------------------------------------
// Zero In Checkers
// ----------------------------------------------------------------------------

// ----------------------------------------------------------------------------
// Combinational
// ----------------------------------------------------------------------------
// output data
  assign dep2cdp_data = data;

// valid command
  wire   vld_cmnd = |d2j_csr_ring_in[`FIRE_CSR_RING_CMND_BITS];

// next state
  always @ (state or vld_cmnd) begin
        nxt_state       = 2'b00;
    case (state) // 0in case -full -parallel
      IDLE : begin
        if (vld_cmnd) nxt_state = RDMS;
        else          nxt_state = IDLE;
      end
      RDMS : nxt_state = RDLS;
      RDLS : nxt_state = IDLE;
     2'b11:  nxt_state = IDLE;
//      default:  nxt_state = 2'bxx;
    endcase
  end

// state outputs
  always @ (state or cmnd) begin
    cmnd_ld = 1'b0;
    data_ld = 2'b00;
    nxt_dne = 1'b0;
    nxt_vio = 1'b0;
    nxt_vld = 1'b0;
    case (state)
      IDLE : begin
        cmnd_ld = 1'b1;
      end
      RDMS : begin
        data_ld = 2'b10;
      end
      RDLS : begin
        data_ld = 2'b01;
        nxt_vld = 1'b1;
        case (cmnd) // synopsys parallel_case
          `FIRE_CSR_CMND_RRSP : begin
            nxt_dne = 1'b1;
            nxt_vio = 1'b0;
          end
          `FIRE_CSR_CMND_WRSP : begin
            nxt_dne = 1'b1;
            nxt_vio = 1'b0;
          end
          `FIRE_CSR_CMND_RERR : begin
            nxt_dne = 1'b1;
            nxt_vio = 1'b1;
          end
          `FIRE_CSR_CMND_WERR : begin
            nxt_dne = 1'b1;
            nxt_vio = 1'b1;
          end
          default : begin
            nxt_dne = 1'b0;
            nxt_vio = 1'b0;
          end
        endcase
      end
        2'b11:  begin
//      default:        begin
                        nxt_vld = 1'b0;         //0in < fire  -message " got x's in dsn_ccc_dep"
                        data_ld = 2'b00;
                        end
    endcase
  end

// ----------------------------------------------------------------------------
// Sequential
// ----------------------------------------------------------------------------
  always @(posedge clk ) begin
    if (!rst_l) begin
      state <= IDLE;
    end
    else begin
      state <= nxt_state;
    end
  end

  always @(posedge clk )
    if (!rst_l) begin
    dep2fsm_acc_vio <= 1'b0;
    dep2fsm_done    <= 1'b0;
    dep2fsm_valid   <= 1'b0;
  end
    else begin
    dep2fsm_acc_vio <= nxt_vio;
    dep2fsm_done    <= nxt_dne;
    dep2fsm_valid   <= nxt_vld;
  end

  always @(posedge clk )
    if (!rst_l) begin
    cmnd                        <= 3'b0;
    data[`FIRE_CSR_RDMS_BITS] <= `FIRE_CSR_RING_WDTH'b0;
    data[`FIRE_CSR_RDLS_BITS] <= `FIRE_CSR_RING_WDTH'b0;
        end
        else begin
    if (cmnd_ld)    cmnd <= d2j_csr_ring_in[`FIRE_CSR_RING_CMND_BITS];
    if (data_ld[1]) data[`FIRE_CSR_RDMS_BITS] <= d2j_csr_ring_in;
    if (data_ld[0]) data[`FIRE_CSR_RDLS_BITS] <= d2j_csr_ring_in;
  end

endmodule // dmu_dsn_ccc_dep