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//----------------------------------------------------------------------------

// Copyright (C) 2009 , Olivier Girard

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions

// are met:

//     * Redistributions of source code must retain the above copyright

//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above copyright

//       notice, this list of conditions and the following disclaimer in the

//       documentation and/or other materials provided with the distribution.

//     * Neither the name of the authors nor the names of its contributors

//       may be used to endorse or promote products derived from this software

//       without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,

// OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

// THE POSSIBILITY OF SUCH DAMAGE

//

//----------------------------------------------------------------------------

//

// *File Name: omsp_dbg.v

// 

// *Module Description:

//                       Debug interface

//

// *Author(s):

//              - Olivier Girard,    olgirard@gmail.com

//

//----------------------------------------------------------------------------

// $Rev: 175 $

// $LastChangedBy: olivier.girard $

// $LastChangedDate: 2013-01-30 22:21:42 +0100 (Wed, 30 Jan 2013) $

//----------------------------------------------------------------------------

`ifdef OMSP_NO_INCLUDE

`else

`include "openMSP430_defines.v"

`endif

module  omsp_dbg (

// OUTPUTs

    dbg_cpu_reset,                     // Reset CPU from debug interface

    dbg_freeze,                        // Freeze peripherals

    dbg_halt_cmd,                      // Halt CPU command

    dbg_i2c_sda_out,                   // Debug interface: I2C SDA OUT

    dbg_mem_addr,                      // Debug address for rd/wr access

    dbg_mem_dout,                      // Debug unit data output

    dbg_mem_en,                        // Debug unit memory enable

    dbg_mem_wr,                        // Debug unit memory write

    dbg_reg_wr,                        // Debug unit CPU register write

    dbg_uart_txd,                      // Debug interface: UART TXD

// INPUTs

    cpu_en_s,                          // Enable CPU code execution (synchronous)

    cpu_id,                            // CPU ID

    cpu_nr_inst,                       // Current oMSP instance number

    cpu_nr_total,                      // Total number of oMSP instances-1

    dbg_clk,                           // Debug unit clock

    dbg_en_s,                          // Debug interface enable (synchronous)

    dbg_halt_st,                       // Halt/Run status from CPU

    dbg_i2c_addr,                      // Debug interface: I2C Address

    dbg_i2c_broadcast,                 // Debug interface: I2C Broadcast Address (for multicore systems)

    dbg_i2c_scl,                       // Debug interface: I2C SCL

    dbg_i2c_sda_in,                    // Debug interface: I2C SDA IN

    dbg_mem_din,                       // Debug unit Memory data input

    dbg_reg_din,                       // Debug unit CPU register data input

    dbg_rst,                           // Debug unit reset

    dbg_uart_rxd,                      // Debug interface: UART RXD (asynchronous)

    decode_noirq,                      // Frontend decode instruction

    eu_mab,                            // Execution-Unit Memory address bus

    eu_mb_en,                          // Execution-Unit Memory bus enable

    eu_mb_wr,                          // Execution-Unit Memory bus write transfer

    fe_mdb_in,                         // Frontend Memory data bus input

    pc,                                // Program counter

    puc_pnd_set                        // PUC pending set for the serial debug interface

);

// OUTPUTs

//=========

output              dbg_cpu_reset;     // Reset CPU from debug interface

output              dbg_freeze;        // Freeze peripherals

output              dbg_halt_cmd;      // Halt CPU command

output              dbg_i2c_sda_out;   // Debug interface: I2C SDA OUT

output       [15:0] dbg_mem_addr;      // Debug address for rd/wr access

output       [15:0] dbg_mem_dout;      // Debug unit data output

output              dbg_mem_en;        // Debug unit memory enable

output        [1:0] dbg_mem_wr;        // Debug unit memory write

output              dbg_reg_wr;        // Debug unit CPU register write

output              dbg_uart_txd;      // Debug interface: UART TXD

// INPUTs

//=========

input               cpu_en_s;          // Enable CPU code execution (synchronous)

input        [31:0] cpu_id;            // CPU ID

input         [7:0] cpu_nr_inst;       // Current oMSP instance number

input         [7:0] cpu_nr_total;      // Total number of oMSP instances-1

input               dbg_clk;           // Debug unit clock

input               dbg_en_s;          // Debug interface enable (synchronous)

input               dbg_halt_st;       // Halt/Run status from CPU

input         [6:0] dbg_i2c_addr;      // Debug interface: I2C Address

input         [6:0] dbg_i2c_broadcast; // Debug interface: I2C Broadcast Address (for multicore systems)

input               dbg_i2c_scl;       // Debug interface: I2C SCL

input               dbg_i2c_sda_in;    // Debug interface: I2C SDA IN

input        [15:0] dbg_mem_din;       // Debug unit Memory data input

input        [15:0] dbg_reg_din;       // Debug unit CPU register data input

input               dbg_rst;           // Debug unit reset

input               dbg_uart_rxd;      // Debug interface: UART RXD (asynchronous)

input               decode_noirq;      // Frontend decode instruction

input        [15:0] eu_mab;            // Execution-Unit Memory address bus

input               eu_mb_en;          // Execution-Unit Memory bus enable

input         [1:0] eu_mb_wr;          // Execution-Unit Memory bus write transfer

input        [15:0] fe_mdb_in;         // Frontend Memory data bus input

input        [15:0] pc;                // Program counter

input               puc_pnd_set;       // PUC pending set for the serial debug interface

//=============================================================================

// 1)  WIRE & PARAMETER DECLARATION

//=============================================================================

// Diverse wires and registers

wire  [5:0] dbg_addr;

wire [15:0] dbg_din;

wire        dbg_wr;

reg         mem_burst;

wire        dbg_reg_rd;

wire        dbg_mem_rd;

reg         dbg_mem_rd_dly;

wire        dbg_swbrk;

wire        dbg_rd;

reg         dbg_rd_rdy;

wire        mem_burst_rd;

wire        mem_burst_wr;

wire        brk0_halt;

wire        brk0_pnd;

wire [15:0] brk0_dout;

wire        brk1_halt;

wire        brk1_pnd;

wire [15:0] brk1_dout;

wire        brk2_halt;

wire        brk2_pnd;

wire [15:0] brk2_dout;

wire        brk3_halt;

wire        brk3_pnd;

wire [15:0] brk3_dout;

// Number of registers

parameter           NR_REG       = 25;

// Register addresses

parameter           CPU_ID_LO    = 6'h00;

parameter           CPU_ID_HI    = 6'h01;

parameter           CPU_CTL      = 6'h02;

parameter           CPU_STAT     = 6'h03;

parameter           MEM_CTL      = 6'h04;

parameter           MEM_ADDR     = 6'h05;

parameter           MEM_DATA     = 6'h06;

parameter           MEM_CNT      = 6'h07;

`ifdef DBG_HWBRK_0

parameter           BRK0_CTL     = 6'h08;

parameter           BRK0_STAT    = 6'h09;

parameter           BRK0_ADDR0   = 6'h0A;

parameter           BRK0_ADDR1   = 6'h0B;

`endif

`ifdef DBG_HWBRK_1

parameter           BRK1_CTL     = 6'h0C;

parameter           BRK1_STAT    = 6'h0D;

parameter           BRK1_ADDR0   = 6'h0E;

parameter           BRK1_ADDR1   = 6'h0F;

`endif

`ifdef DBG_HWBRK_2

parameter           BRK2_CTL     = 6'h10;

parameter           BRK2_STAT    = 6'h11;

parameter           BRK2_ADDR0   = 6'h12;

parameter           BRK2_ADDR1   = 6'h13;

`endif

`ifdef DBG_HWBRK_3

parameter           BRK3_CTL     = 6'h14;

parameter           BRK3_STAT    = 6'h15;

parameter           BRK3_ADDR0   = 6'h16;

parameter           BRK3_ADDR1   = 6'h17;

`endif

parameter           CPU_NR       = 6'h18;

// Register one-hot decoder

parameter           BASE_D       = {{NR_REG-1{1'b0}}, 1'b1};

parameter           CPU_ID_LO_D  = (BASE_D << CPU_ID_LO);

parameter           CPU_ID_HI_D  = (BASE_D << CPU_ID_HI);

parameter           CPU_CTL_D    = (BASE_D << CPU_CTL);

parameter           CPU_STAT_D   = (BASE_D << CPU_STAT);

parameter           MEM_CTL_D    = (BASE_D << MEM_CTL);

parameter           MEM_ADDR_D   = (BASE_D << MEM_ADDR);

parameter           MEM_DATA_D   = (BASE_D << MEM_DATA);

parameter           MEM_CNT_D    = (BASE_D << MEM_CNT);

`ifdef DBG_HWBRK_0

parameter           BRK0_CTL_D   = (BASE_D << BRK0_CTL);

parameter           BRK0_STAT_D  = (BASE_D << BRK0_STAT);

parameter           BRK0_ADDR0_D = (BASE_D << BRK0_ADDR0);

parameter           BRK0_ADDR1_D = (BASE_D << BRK0_ADDR1);

`endif

`ifdef DBG_HWBRK_1

parameter           BRK1_CTL_D   = (BASE_D << BRK1_CTL);

parameter           BRK1_STAT_D  = (BASE_D << BRK1_STAT);

parameter           BRK1_ADDR0_D = (BASE_D << BRK1_ADDR0);

parameter           BRK1_ADDR1_D = (BASE_D << BRK1_ADDR1);

`endif

`ifdef DBG_HWBRK_2

parameter           BRK2_CTL_D   = (BASE_D << BRK2_CTL);

parameter           BRK2_STAT_D  = (BASE_D << BRK2_STAT);

parameter           BRK2_ADDR0_D = (BASE_D << BRK2_ADDR0);

parameter           BRK2_ADDR1_D = (BASE_D << BRK2_ADDR1);

`endif

`ifdef DBG_HWBRK_3

parameter           BRK3_CTL_D   = (BASE_D << BRK3_CTL);

parameter           BRK3_STAT_D  = (BASE_D << BRK3_STAT);

parameter           BRK3_ADDR0_D = (BASE_D << BRK3_ADDR0);

parameter           BRK3_ADDR1_D = (BASE_D << BRK3_ADDR1);

`endif

parameter           CPU_NR_D     = (BASE_D << CPU_NR);

//============================================================================

// 2)  REGISTER DECODER

//============================================================================

// Select Data register during a burst

wire  [5:0] dbg_addr_in = mem_burst ? MEM_DATA : dbg_addr;

// Register address decode

reg  [NR_REG-1:0]  reg_dec;

always @(dbg_addr_in)

  case (dbg_addr_in)

    CPU_ID_LO :  reg_dec  =  CPU_ID_LO_D;

    CPU_ID_HI :  reg_dec  =  CPU_ID_HI_D;

    CPU_CTL   :  reg_dec  =  CPU_CTL_D;

    CPU_STAT  :  reg_dec  =  CPU_STAT_D;

    MEM_CTL   :  reg_dec  =  MEM_CTL_D;

    MEM_ADDR  :  reg_dec  =  MEM_ADDR_D;

    MEM_DATA  :  reg_dec  =  MEM_DATA_D;

    MEM_CNT   :  reg_dec  =  MEM_CNT_D;

`ifdef DBG_HWBRK_0

    BRK0_CTL  :  reg_dec  =  BRK0_CTL_D;

    BRK0_STAT :  reg_dec  =  BRK0_STAT_D;

    BRK0_ADDR0:  reg_dec  =  BRK0_ADDR0_D;

    BRK0_ADDR1:  reg_dec  =  BRK0_ADDR1_D;

`endif

`ifdef DBG_HWBRK_1

    BRK1_CTL  :  reg_dec  =  BRK1_CTL_D;

    BRK1_STAT :  reg_dec  =  BRK1_STAT_D;

    BRK1_ADDR0:  reg_dec  =  BRK1_ADDR0_D;

    BRK1_ADDR1:  reg_dec  =  BRK1_ADDR1_D;

`endif

`ifdef DBG_HWBRK_2

    BRK2_CTL  :  reg_dec  =  BRK2_CTL_D;

    BRK2_STAT :  reg_dec  =  BRK2_STAT_D;

    BRK2_ADDR0:  reg_dec  =  BRK2_ADDR0_D;

    BRK2_ADDR1:  reg_dec  =  BRK2_ADDR1_D;

`endif

`ifdef DBG_HWBRK_3

    BRK3_CTL  :  reg_dec  =  BRK3_CTL_D;

    BRK3_STAT :  reg_dec  =  BRK3_STAT_D;

    BRK3_ADDR0:  reg_dec  =  BRK3_ADDR0_D;

    BRK3_ADDR1:  reg_dec  =  BRK3_ADDR1_D;

`endif

    CPU_NR    :  reg_dec  =  CPU_NR_D;

  // pragma coverage off

    default:     reg_dec  =  {NR_REG{1'b0}};

  // pragma coverage on

  endcase

// Read/Write probes

wire               reg_write =  dbg_wr;

wire               reg_read  =  1'b1;

// Read/Write vectors

wire  [NR_REG-1:0] reg_wr    = reg_dec & {NR_REG{reg_write}};

wire  [NR_REG-1:0] reg_rd    = reg_dec & {NR_REG{reg_read}};

//=============================================================================

// 3)  REGISTER: CORE INTERFACE

//=============================================================================

// CPU_ID Register

//-----------------   

//              -------------------------------------------------------------------

// CPU_ID_LO:  | 15  14  13  12  11  10  9  |  8  7  6  5  4  |  3   |   2  1  0   |

//             |----------------------------+-----------------+------+-------------|

//             |        PER_SPACE           |   USER_VERSION  | ASIC | CPU_VERSION |

//              --------------------------------------------------------------------

// CPU_ID_HI:  |   15  14  13  12  11  10   |   9  8  7  6  5  4  3  2  1   |   0  |

//             |----------------------------+-------------------------------+------|

//             |         PMEM_SIZE          |            DMEM_SIZE          |  MPY |

//              -------------------------------------------------------------------

// This register is assigned in the SFR module

// CPU_NR Register

//-----------------

//    -------------------------------------------------------------------

//   | 15  14  13  12  11  10   9   8  |  7   6   5   4   3   2   1   0  |

//   |---------------------------------+---------------------------------|

//   |            CPU_TOTAL_NR         |           CPU_INST_NR           |

//    -------------------------------------------------------------------

wire [15:0] cpu_nr = {cpu_nr_total, cpu_nr_inst};

// CPU_CTL Register

//-----------------------------------------------------------------------------

//       7         6          5          4           3        2     1    0

//   Reserved   CPU_RST  RST_BRK_EN  FRZ_BRK_EN  SW_BRK_EN  ISTEP  RUN  HALT

//-----------------------------------------------------------------------------

reg   [6:3] cpu_ctl;

wire        cpu_ctl_wr = reg_wr[CPU_CTL];

always @ (posedge dbg_clk or posedge dbg_rst)

`ifdef DBG_RST_BRK_EN

  if (dbg_rst)         cpu_ctl <=  4'h6;

`else

  if (dbg_rst)         cpu_ctl <=  4'h2;

`endif

  else if (cpu_ctl_wr) cpu_ctl <=  dbg_din[6:3];

wire  [7:0] cpu_ctl_full = {1'b0, cpu_ctl, 3'b000};

wire        halt_cpu = cpu_ctl_wr & dbg_din[`HALT]  & ~dbg_halt_st;

wire        run_cpu  = cpu_ctl_wr & dbg_din[`RUN]   &  dbg_halt_st;

wire        istep    = cpu_ctl_wr & dbg_din[`ISTEP] &  dbg_halt_st;

// CPU_STAT Register

//------------------------------------------------------------------------------------

//      7           6          5           4           3         2      1       0

// HWBRK3_PND  HWBRK2_PND  HWBRK1_PND  HWBRK0_PND  SWBRK_PND  PUC_PND  Res.  HALT_RUN

//------------------------------------------------------------------------------------

reg   [3:2] cpu_stat;

wire        cpu_stat_wr  = reg_wr[CPU_STAT];

wire  [3:2] cpu_stat_set = {dbg_swbrk, puc_pnd_set};

wire  [3:2] cpu_stat_clr = ~dbg_din[3:2];

always @ (posedge dbg_clk or posedge dbg_rst)

  if (dbg_rst)          cpu_stat <=  2'b00;

  else if (cpu_stat_wr) cpu_stat <= ((cpu_stat & cpu_stat_clr) | cpu_stat_set);

  else                  cpu_stat <=  (cpu_stat                 | cpu_stat_set);

wire  [7:0] cpu_stat_full = {brk3_pnd, brk2_pnd, brk1_pnd, brk0_pnd,

                             cpu_stat, 1'b0, dbg_halt_st};

//=============================================================================

// 4)  REGISTER: MEMORY INTERFACE

//=============================================================================

// MEM_CTL Register

//-----------------------------------------------------------------------------

//       7     6     5     4          3        2         1       0

//            Reserved               B/W    MEM/REG    RD/WR   START

//

// START  :  -  0 : Do nothing.

//           -  1 : Initiate memory transfer.

//

// RD/WR  :  -  0 : Read access.

//           -  1 : Write access.

//

// MEM/REG:  -  0 : Memory access.

//           -  1 : CPU Register access.

//

// B/W    :  -  0 : 16 bit access.

//           -  1 :  8 bit access (not valid for CPU Registers).

//

//-----------------------------------------------------------------------------

reg   [3:1] mem_ctl;

wire        mem_ctl_wr = reg_wr[MEM_CTL];

always @ (posedge dbg_clk or posedge dbg_rst)

  if (dbg_rst)         mem_ctl <=  3'h0;

  else if (mem_ctl_wr) mem_ctl <=  dbg_din[3:1];

wire  [7:0] mem_ctl_full  = {4'b0000, mem_ctl, 1'b0};

reg         mem_start;

always @ (posedge dbg_clk or posedge dbg_rst)

  if (dbg_rst)  mem_start <=  1'b0;

  else          mem_start <=  mem_ctl_wr & dbg_din[0];

wire        mem_bw    = mem_ctl[3];

// MEM_DATA Register

//------------------   

reg  [15:0] mem_data;

reg  [15:0] mem_addr;

wire        mem_access;

wire        mem_data_wr = reg_wr[MEM_DATA];

wire [15:0] dbg_mem_din_bw = ~mem_bw      ? dbg_mem_din                :

                              mem_addr[0] ? {8'h00, dbg_mem_din[15:8]} :

                                            {8'h00, dbg_mem_din[7:0]};

always @ (posedge dbg_clk or posedge dbg_rst)

  if (dbg_rst)             mem_data <=  16'h0000;

  else if (mem_data_wr)    mem_data <=  dbg_din;

  else if (dbg_reg_rd)     mem_data <=  dbg_reg_din;

  else if (dbg_mem_rd_dly) mem_data <=  dbg_mem_din_bw;

// MEM_ADDR Register

//------------------   

reg  [15:0] mem_cnt;

wire        mem_addr_wr  = reg_wr[MEM_ADDR];

wire        dbg_mem_acc  = (|dbg_mem_wr | (dbg_rd_rdy & ~mem_ctl[2]));

wire        dbg_reg_acc  = ( dbg_reg_wr | (dbg_rd_rdy &  mem_ctl[2]));

wire [15:0] mem_addr_inc = (mem_cnt==16'h0000)                       ? 16'h0000 :

                           (mem_burst &  dbg_mem_acc & ~mem_bw)      ? 16'h0002 :

                           (mem_burst & (dbg_mem_acc | dbg_reg_acc)) ? 16'h0001 : 16'h0000;

always @ (posedge dbg_clk or posedge dbg_rst)

  if (dbg_rst)          mem_addr <=  16'h0000;

  else if (mem_addr_wr) mem_addr <=  dbg_din;

  else                  mem_addr <=  mem_addr + mem_addr_inc;

// MEM_CNT Register

//------------------   

wire        mem_cnt_wr  = reg_wr[MEM_CNT];

wire [15:0] mem_cnt_dec = (mem_cnt==16'h0000)                       ? 16'h0000 :

                          (mem_burst & (dbg_mem_acc | dbg_reg_acc)) ? 16'hffff : 16'h0000;

always @ (posedge dbg_clk or posedge dbg_rst)

  if (dbg_rst)         mem_cnt <=  16'h0000;

  else if (mem_cnt_wr) mem_cnt <=  dbg_din;

  else                 mem_cnt <=  mem_cnt + mem_cnt_dec;

//=============================================================================

// 5)  BREAKPOINTS / WATCHPOINTS

//=============================================================================

`ifdef DBG_HWBRK_0

// Hardware Breakpoint/Watchpoint Register read select

wire [3:0] brk0_reg_rd = {reg_rd[BRK0_ADDR1],

                          reg_rd[BRK0_ADDR0],

                          reg_rd[BRK0_STAT],

                          reg_rd[BRK0_CTL]};

// Hardware Breakpoint/Watchpoint Register write select

wire [3:0] brk0_reg_wr = {reg_wr[BRK0_ADDR1],

                          reg_wr[BRK0_ADDR0],

                          reg_wr[BRK0_STAT],

                          reg_wr[BRK0_CTL]};

omsp_dbg_hwbrk dbg_hwbr_0 (

// OUTPUTs

    .brk_halt     (brk0_halt),    // Hardware breakpoint command

    .brk_pnd      (brk0_pnd),     // Hardware break/watch-point pending

    .brk_dout     (brk0_dout),    // Hardware break/watch-point register data input

// INPUTs

    .brk_reg_rd   (brk0_reg_rd),  // Hardware break/watch-point register read select

    .brk_reg_wr   (brk0_reg_wr),  // Hardware break/watch-point register write select

    .dbg_clk      (dbg_clk),      // Debug unit clock

    .dbg_din      (dbg_din),      // Debug register data input

    .dbg_rst      (dbg_rst),      // Debug unit reset

    .decode_noirq (decode_noirq), // Frontend decode instruction

    .eu_mab       (eu_mab),       // Execution-Unit Memory address bus

    .eu_mb_en     (eu_mb_en),     // Execution-Unit Memory bus enable

    .eu_mb_wr     (eu_mb_wr),     // Execution-Unit Memory bus write transfer

    .pc           (pc)            // Program counter

);

`else

assign brk0_halt =  1'b0;

assign brk0_pnd  =  1'b0;

assign brk0_dout = 16'h0000;

`endif

`ifdef DBG_HWBRK_1

// Hardware Breakpoint/Watchpoint Register read select

wire [3:0] brk1_reg_rd = {reg_rd[BRK1_ADDR1],

                          reg_rd[BRK1_ADDR0],

                          reg_rd[BRK1_STAT],

                          reg_rd[BRK1_CTL]};

// Hardware Breakpoint/Watchpoint Register write select

wire [3:0] brk1_reg_wr = {reg_wr[BRK1_ADDR1],

                          reg_wr[BRK1_ADDR0],

                          reg_wr[BRK1_STAT],

                          reg_wr[BRK1_CTL]};

omsp_dbg_hwbrk dbg_hwbr_1 (

// OUTPUTs

    .brk_halt     (brk1_halt),    // Hardware breakpoint command

    .brk_pnd      (brk1_pnd),     // Hardware break/watch-point pending

    .brk_dout     (brk1_dout),    // Hardware break/watch-point register data input

// INPUTs

    .brk_reg_rd   (brk1_reg_rd),  // Hardware break/watch-point register read select

    .brk_reg_wr   (brk1_reg_wr),  // Hardware break/watch-point register write select

    .dbg_clk      (dbg_clk),      // Debug unit clock

    .dbg_din      (dbg_din),      // Debug register data input

    .dbg_rst      (dbg_rst),      // Debug unit reset

    .decode_noirq (decode_noirq), // Frontend decode instruction

    .eu_mab       (eu_mab),       // Execution-Unit Memory address bus

    .eu_mb_en     (eu_mb_en),     // Execution-Unit Memory bus enable

    .eu_mb_wr     (eu_mb_wr),     // Execution-Unit Memory bus write transfer

    .pc           (pc)            // Program counter

);

`else

assign brk1_halt =  1'b0;

assign brk1_pnd  =  1'b0;

assign brk1_dout = 16'h0000;

`endif

 `ifdef DBG_HWBRK_2

// Hardware Breakpoint/Watchpoint Register read select

wire [3:0] brk2_reg_rd = {reg_rd[BRK2_ADDR1],

                          reg_rd[BRK2_ADDR0],

                          reg_rd[BRK2_STAT],

                          reg_rd[BRK2_CTL]};

// Hardware Breakpoint/Watchpoint Register write select

wire [3:0] brk2_reg_wr = {reg_wr[BRK2_ADDR1],

                          reg_wr[BRK2_ADDR0],

                          reg_wr[BRK2_STAT],

                          reg_wr[BRK2_CTL]};

omsp_dbg_hwbrk dbg_hwbr_2 (

// OUTPUTs

    .brk_halt     (brk2_halt),    // Hardware breakpoint command

    .brk_pnd      (brk2_pnd),     // Hardware break/watch-point pending

    .brk_dout     (brk2_dout),    // Hardware break/watch-point register data input

// INPUTs

    .brk_reg_rd   (brk2_reg_rd),  // Hardware break/watch-point register read select

    .brk_reg_wr   (brk2_reg_wr),  // Hardware break/watch-point register write select

    .dbg_clk      (dbg_clk),      // Debug unit clock

    .dbg_din      (dbg_din),      // Debug register data input

    .dbg_rst      (dbg_rst),      // Debug unit reset

    .decode_noirq (decode_noirq), // Frontend decode instruction

    .eu_mab       (eu_mab),       // Execution-Unit Memory address bus

    .eu_mb_en     (eu_mb_en),     // Execution-Unit Memory bus enable

    .eu_mb_wr     (eu_mb_wr),     // Execution-Unit Memory bus write transfer

    .pc           (pc)            // Program counter

);

`else

assign brk2_halt =  1'b0;

assign brk2_pnd  =  1'b0;

assign brk2_dout = 16'h0000;

`endif

`ifdef DBG_HWBRK_3

// Hardware Breakpoint/Watchpoint Register read select

wire [3:0] brk3_reg_rd = {reg_rd[BRK3_ADDR1],

                          reg_rd[BRK3_ADDR0],

                          reg_rd[BRK3_STAT],

                          reg_rd[BRK3_CTL]};

// Hardware Breakpoint/Watchpoint Register write select

wire [3:0] brk3_reg_wr = {reg_wr[BRK3_ADDR1],

                          reg_wr[BRK3_ADDR0],

                          reg_wr[BRK3_STAT],

                          reg_wr[BRK3_CTL]};

omsp_dbg_hwbrk dbg_hwbr_3 (

// OUTPUTs

    .brk_halt     (brk3_halt),    // Hardware breakpoint command

    .brk_pnd      (brk3_pnd),     // Hardware break/watch-point pending

    .brk_dout     (brk3_dout),    // Hardware break/watch-point register data input

// INPUTs

    .brk_reg_rd   (brk3_reg_rd),  // Hardware break/watch-point register read select

    .brk_reg_wr   (brk3_reg_wr),  // Hardware break/watch-point register write select

    .dbg_clk      (dbg_clk),      // Debug unit clock

    .dbg_din      (dbg_din),      // Debug register data input

    .dbg_rst      (dbg_rst),      // Debug unit reset

    .decode_noirq (decode_noirq), // Frontend decode instruction

    .eu_mab       (eu_mab),       // Execution-Unit Memory address bus

    .eu_mb_en     (eu_mb_en),     // Execution-Unit Memory bus enable

    .eu_mb_wr     (eu_mb_wr),     // Execution-Unit Memory bus write transfer

    .pc           (pc)            // Program counter

);

`else

assign brk3_halt =  1'b0;

assign brk3_pnd  =  1'b0;

assign brk3_dout = 16'h0000;

`endif

//============================================================================

// 6) DATA OUTPUT GENERATION

//============================================================================

wire [15:0] cpu_id_lo_rd = cpu_id[15:0]           & {16{reg_rd[CPU_ID_LO]}};

wire [15:0] cpu_id_hi_rd = cpu_id[31:16]          & {16{reg_rd[CPU_ID_HI]}};

wire [15:0] cpu_ctl_rd   = {8'h00, cpu_ctl_full}  & {16{reg_rd[CPU_CTL]}};

wire [15:0] cpu_stat_rd  = {8'h00, cpu_stat_full} & {16{reg_rd[CPU_STAT]}};

wire [15:0] mem_ctl_rd   = {8'h00, mem_ctl_full}  & {16{reg_rd[MEM_CTL]}};

wire [15:0] mem_data_rd  = mem_data               & {16{reg_rd[MEM_DATA]}};

wire [15:0] mem_addr_rd  = mem_addr               & {16{reg_rd[MEM_ADDR]}};

wire [15:0] mem_cnt_rd   = mem_cnt                & {16{reg_rd[MEM_CNT]}};

wire [15:0] cpu_nr_rd    = cpu_nr                 & {16{reg_rd[CPU_NR]}};

wire [15:0] dbg_dout = cpu_id_lo_rd |