IPCores/lm32_cpu: lm32_cpu.v@73de224304c1 (annotated)

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lm32_cpu.v@73de224304c1 (annotated)

lm32_cpu.v

Sat, 06 Aug 2011 00:02:46 +0100

author: Philip Pemberton <philpem@philpem.me.uk>
date: Sat, 06 Aug 2011 00:02:46 +0100
changeset 26: 73de224304c1
parent 22: 35dc7ba83714
child 27: d6c693415d59
permissions: -rwxr-xr-x

[UPSTREAM PULL] Update baseline to LatticeMico32 v3.8 from Diamond 1.3-lm32 distribution package (datestamp May 2011)

 //   ==================================================================
 //   >>>>>>>>>>>>>>>>>>>>>>> COPYRIGHT NOTICE <<<<<<<<<<<<<<<<<<<<<<<<<
 //   ------------------------------------------------------------------
 //   Copyright (c) 2006-2011 by Lattice Semiconductor Corporation
 //   ALL RIGHTS RESERVED
 //   ------------------------------------------------------------------
 //
 //   IMPORTANT: THIS FILE IS AUTO-GENERATED BY THE LATTICEMICO SYSTEM.
 //
 //   Permission:
 //
 //      Lattice Semiconductor grants permission to use this code
 //      pursuant to the terms of the Lattice Semiconductor Corporation
 //      Open Source License Agreement.
 //
 //   Disclaimer:
 //
 //      Lattice Semiconductor provides no warranty regarding the use or
 //      functionality of this code. It is the user's responsibility to
 //      verify the user’s design for consistency and functionality through
 //      the use of formal verification methods.
 //
 //   --------------------------------------------------------------------
 //
 //                  Lattice Semiconductor Corporation
 //                  5555 NE Moore Court
 //                  Hillsboro, OR 97214
 //                  U.S.A
 //
 //                  TEL: 1-800-Lattice (USA and Canada)
 //                         503-286-8001 (other locations)
 //
 //                  web: http://www.latticesemi.com/
 //                  email: techsupport@latticesemi.com
 //
 //   --------------------------------------------------------------------
 //                         FILE DETAILS
 // Project          : LatticeMico32
 // File             : lm32_cpu.v
 // Title            : Top-level of CPU.
 // Dependencies     : lm32_include.v
 //
 // Version 3.8
 // 1. Feature: Support for dynamically switching EBA to DEBA via a GPIO.
 // 2. Bug: EA now reports instruction that caused the data abort, rather than
 //    next instruction.
 //
 // Version 3.4
 // 1. Bug Fix: In a tight infinite loop (add, sw, bi) incoming interrupts were
 //    never serviced.
 //
 // Version 3.3
 // 1. Feature: Support for memory that is tightly coupled to processor core, and
 //    has a single-cycle access latency (same as caches). Instruction port has
 //    access to a dedicated physically-mapped memory. Data port has access to
 //    a dedicated physically-mapped memory. In order to be able to manipulate
 //    values in both these memories via the debugger, these memories also
 //    interface with the data port of LM32.
 // 2. Feature: Extended Configuration Register
 // 3. Bug Fix: Removed port names that conflict with keywords reserved in System-
 //    Verilog.
 //
 // Version 3.2
 // 1. Bug Fix: Single-stepping a load/store to invalid address causes debugger to
 //    hang. At the same time CPU fails to register data bus error exception. Bug
 //    is caused because (a) data bus error exception occurs after load/store has
 //    passed X stage and next sequential instruction (e.g., brk) is already in X
 //    stage, and (b) data bus error exception had lower priority than, say, brk
 //    exception.
 // 2. Bug Fix: If a brk (or scall/eret/bret) sequentially follows a load/store to
 //    invalid location, CPU will fail to register data bus error exception. The
 //    solution is to stall scall/eret/bret/brk instructions in D pipeline stage
 //    until load/store has completed.
 // 3. Feature: Enable precise identification of load/store that causes seg fault.
 // 4. SYNC resets used for register file when implemented in EBRs.
 //
 // Version 3.1
 // 1. Feature: LM32 Register File can now be mapped in to on-chip block RAM (EBR)
 //    instead of distributed memory by enabling the option in LM32 GUI.
 // 2. Feature: LM32 also adds a static branch predictor to improve branch
 //    performance. All immediate-based forward-pointing branches are predicted
 //    not-taken. All immediate-based backward-pointing branches are predicted taken.
 //
 // Version 7.0SP2, 3.0
 // No Change
 //
 // Version 6.1.17
 // Initial Release
 // =============================================================================
 `include "lm32_include.v"
 /////////////////////////////////////////////////////
 // Module interface
 /////////////////////////////////////////////////////
 module lm32_cpu (
     // ----- Inputs -------
     clk_i,
 `ifdef CFG_EBR_NEGEDGE_REGISTER_FILE
     clk_n_i,
 `endif
     rst_i,
 `ifdef CFG_DEBUG_ENABLED
  `ifdef CFG_ALTERNATE_EBA
     at_debug,
  `endif
 `endif
     // From external devices
 `ifdef CFG_INTERRUPTS_ENABLED
     interrupt_n,
 `endif
     // From user logic
 `ifdef CFG_USER_ENABLED
     user_result,
     user_complete,
 `endif
 `ifdef CFG_JTAG_ENABLED
     // From JTAG
     jtag_clk,
     jtag_update,
     jtag_reg_q,
     jtag_reg_addr_q,
 `endif
 `ifdef CFG_IWB_ENABLED
     // Instruction Wishbone master
     I_DAT_I,
     I_ACK_I,
     I_ERR_I,
     I_RTY_I,
 `endif
     // Data Wishbone master
     D_DAT_I,
     D_ACK_I,
     D_ERR_I,
     D_RTY_I,
     // ----- Outputs -------
 `ifdef CFG_TRACE_ENABLED
     trace_pc,
     trace_pc_valid,
     trace_exception,
     trace_eid,
     trace_eret,
 `ifdef CFG_DEBUG_ENABLED
     trace_bret,
 `endif
 `endif
 `ifdef CFG_JTAG_ENABLED
     jtag_reg_d,
     jtag_reg_addr_d,
 `endif
 `ifdef CFG_USER_ENABLED
     user_valid,
     user_opcode,
     user_operand_0,
     user_operand_1,
 `endif
 `ifdef CFG_IWB_ENABLED
     // Instruction Wishbone master
     I_DAT_O,
     I_ADR_O,
     I_CYC_O,
     I_SEL_O,
     I_STB_O,
     I_WE_O,
     I_CTI_O,
     I_LOCK_O,
     I_BTE_O,
 `endif
     // Data Wishbone master
     D_DAT_O,
     D_ADR_O,
     D_CYC_O,
     D_SEL_O,
     D_STB_O,
     D_WE_O,
     D_CTI_O,
     D_LOCK_O,
     D_BTE_O
     );
 /////////////////////////////////////////////////////
 // Parameters
 /////////////////////////////////////////////////////
 parameter eba_reset = `CFG_EBA_RESET;                           // Reset value for EBA CSR
 `ifdef CFG_DEBUG_ENABLED
 parameter deba_reset = `CFG_DEBA_RESET;                         // Reset value for DEBA CSR
 `endif
 `ifdef CFG_ICACHE_ENABLED
 parameter icache_associativity = `CFG_ICACHE_ASSOCIATIVITY;     // Associativity of the cache (Number of ways)
 parameter icache_sets = `CFG_ICACHE_SETS;                       // Number of sets
 parameter icache_bytes_per_line = `CFG_ICACHE_BYTES_PER_LINE;   // Number of bytes per cache line
 parameter icache_base_address = `CFG_ICACHE_BASE_ADDRESS;       // Base address of cachable memory
 parameter icache_limit = `CFG_ICACHE_LIMIT;                     // Limit (highest address) of cachable memory
 `else
 parameter icache_associativity = 1;
 parameter icache_sets = 512;
 parameter icache_bytes_per_line = 16;
 parameter icache_base_address = 0;
 parameter icache_limit = 0;
 `endif
 `ifdef CFG_DCACHE_ENABLED
 parameter dcache_associativity = `CFG_DCACHE_ASSOCIATIVITY;     // Associativity of the cache (Number of ways)
 parameter dcache_sets = `CFG_DCACHE_SETS;                       // Number of sets
 parameter dcache_bytes_per_line = `CFG_DCACHE_BYTES_PER_LINE;   // Number of bytes per cache line
 parameter dcache_base_address = `CFG_DCACHE_BASE_ADDRESS;       // Base address of cachable memory
 parameter dcache_limit = `CFG_DCACHE_LIMIT;                     // Limit (highest address) of cachable memory
 `else
 parameter dcache_associativity = 1;
 parameter dcache_sets = 512;
 parameter dcache_bytes_per_line = 16;
 parameter dcache_base_address = 0;
 parameter dcache_limit = 0;
 `endif
 `ifdef CFG_DEBUG_ENABLED
 parameter watchpoints = `CFG_WATCHPOINTS;                       // Number of h/w watchpoint CSRs
 `else
 parameter watchpoints = 0;
 `endif
 `ifdef CFG_ROM_DEBUG_ENABLED
 parameter breakpoints = `CFG_BREAKPOINTS;                       // Number of h/w breakpoint CSRs
 `else
 parameter breakpoints = 0;
 `endif
 `ifdef CFG_INTERRUPTS_ENABLED
 parameter interrupts = `CFG_INTERRUPTS;                         // Number of interrupts
 `else
 parameter interrupts = 0;
 `endif
 /////////////////////////////////////////////////////
 // Inputs
 /////////////////////////////////////////////////////
 input clk_i;                                    // Clock
 `ifdef CFG_EBR_NEGEDGE_REGISTER_FILE
 input clk_n_i;                                  // Inverted clock
 `endif
 input rst_i;                                    // Reset
 `ifdef CFG_DEBUG_ENABLED
  `ifdef CFG_ALTERNATE_EBA
    input at_debug;                              // GPIO input that maps EBA to DEBA
  `endif
 `endif
 `ifdef CFG_INTERRUPTS_ENABLED
 input [`LM32_INTERRUPT_RNG] interrupt_n;        // Interrupt pins, active-low
 `endif
 `ifdef CFG_USER_ENABLED
 input [`LM32_WORD_RNG] user_result;             // User-defined instruction result
 input user_complete;                            // User-defined instruction execution is complete
 `endif
 `ifdef CFG_JTAG_ENABLED
 input jtag_clk;                                 // JTAG clock
 input jtag_update;                              // JTAG state machine is in data register update state
 input [`LM32_BYTE_RNG] jtag_reg_q;
 input [2:0] jtag_reg_addr_q;
 `endif
 `ifdef CFG_IWB_ENABLED
 input [`LM32_WORD_RNG] I_DAT_I;                 // Instruction Wishbone interface read data
 input I_ACK_I;                                  // Instruction Wishbone interface acknowledgement
 input I_ERR_I;                                  // Instruction Wishbone interface error
 input I_RTY_I;                                  // Instruction Wishbone interface retry
 `endif
 input [`LM32_WORD_RNG] D_DAT_I;                 // Data Wishbone interface read data
 input D_ACK_I;                                  // Data Wishbone interface acknowledgement
 input D_ERR_I;                                  // Data Wishbone interface error
 input D_RTY_I;                                  // Data Wishbone interface retry
 /////////////////////////////////////////////////////
 // Outputs
 /////////////////////////////////////////////////////
 `ifdef CFG_TRACE_ENABLED
 output [`LM32_PC_RNG] trace_pc;                 // PC to trace
 reg    [`LM32_PC_RNG] trace_pc;
 output trace_pc_valid;                          // Indicates that a new trace PC is valid
 reg    trace_pc_valid;
 output trace_exception;                         // Indicates an exception has occured
 reg    trace_exception;
 output [`LM32_EID_RNG] trace_eid;               // Indicates what type of exception has occured
 reg    [`LM32_EID_RNG] trace_eid;
 output trace_eret;                              // Indicates an eret instruction has been executed
 reg    trace_eret;
 `ifdef CFG_DEBUG_ENABLED
 output trace_bret;                              // Indicates a bret instruction has been executed
 reg    trace_bret;
 `endif
 `endif
 `ifdef CFG_JTAG_ENABLED
 output [`LM32_BYTE_RNG] jtag_reg_d;
 wire   [`LM32_BYTE_RNG] jtag_reg_d;
 output [2:0] jtag_reg_addr_d;
 wire   [2:0] jtag_reg_addr_d;
 `endif
 `ifdef CFG_USER_ENABLED
 output user_valid;                              // Indicates if user_opcode is valid
 wire   user_valid;
 output [`LM32_USER_OPCODE_RNG] user_opcode;     // User-defined instruction opcode
 reg    [`LM32_USER_OPCODE_RNG] user_opcode;
 output [`LM32_WORD_RNG] user_operand_0;         // First operand for user-defined instruction
 wire   [`LM32_WORD_RNG] user_operand_0;
 output [`LM32_WORD_RNG] user_operand_1;         // Second operand for user-defined instruction
 wire   [`LM32_WORD_RNG] user_operand_1;
 `endif
 `ifdef CFG_IWB_ENABLED
 output [`LM32_WORD_RNG] I_DAT_O;                // Instruction Wishbone interface write data
 wire   [`LM32_WORD_RNG] I_DAT_O;
 output [`LM32_WORD_RNG] I_ADR_O;                // Instruction Wishbone interface address
 wire   [`LM32_WORD_RNG] I_ADR_O;
 output I_CYC_O;                                 // Instruction Wishbone interface cycle
 wire   I_CYC_O;
 output [`LM32_BYTE_SELECT_RNG] I_SEL_O;         // Instruction Wishbone interface byte select
 wire   [`LM32_BYTE_SELECT_RNG] I_SEL_O;
 output I_STB_O;                                 // Instruction Wishbone interface strobe
 wire   I_STB_O;
 output I_WE_O;                                  // Instruction Wishbone interface write enable
 wire   I_WE_O;
 output [`LM32_CTYPE_RNG] I_CTI_O;               // Instruction Wishbone interface cycle type
 wire   [`LM32_CTYPE_RNG] I_CTI_O;
 output I_LOCK_O;                                // Instruction Wishbone interface lock bus
 wire   I_LOCK_O;
 output [`LM32_BTYPE_RNG] I_BTE_O;               // Instruction Wishbone interface burst type
 wire   [`LM32_BTYPE_RNG] I_BTE_O;
 `endif
 output [`LM32_WORD_RNG] D_DAT_O;                // Data Wishbone interface write data
 wire   [`LM32_WORD_RNG] D_DAT_O;
 output [`LM32_WORD_RNG] D_ADR_O;                // Data Wishbone interface address
 wire   [`LM32_WORD_RNG] D_ADR_O;
 output D_CYC_O;                                 // Data Wishbone interface cycle
 wire   D_CYC_O;
 output [`LM32_BYTE_SELECT_RNG] D_SEL_O;         // Data Wishbone interface byte select
 wire   [`LM32_BYTE_SELECT_RNG] D_SEL_O;
 output D_STB_O;                                 // Data Wishbone interface strobe
 wire   D_STB_O;
 output D_WE_O;                                  // Data Wishbone interface write enable
 wire   D_WE_O;
 output [`LM32_CTYPE_RNG] D_CTI_O;               // Data Wishbone interface cycle type
 wire   [`LM32_CTYPE_RNG] D_CTI_O;
 output D_LOCK_O;                                // Date Wishbone interface lock bus
 wire   D_LOCK_O;
 output [`LM32_BTYPE_RNG] D_BTE_O;               // Data Wishbone interface burst type
 wire   [`LM32_BTYPE_RNG] D_BTE_O;
 /////////////////////////////////////////////////////
 // Internal nets and registers
 /////////////////////////////////////////////////////
 // Pipeline registers
 `ifdef LM32_CACHE_ENABLED
 reg valid_a;                                    // Instruction in A stage is valid
 `endif
 reg valid_f;                                    // Instruction in F stage is valid
 reg valid_d;                                    // Instruction in D stage is valid
 reg valid_x;                                    // Instruction in X stage is valid
 reg valid_m;                                    // Instruction in M stage is valid
 reg valid_w;                                    // Instruction in W stage is valid
 wire q_x;
 wire [`LM32_WORD_RNG] immediate_d;              // Immediate operand
 wire load_d;                                    // Indicates a load instruction
 reg load_x;
 reg load_m;
 wire load_q_x;
 wire store_q_x;
 wire store_d;                                   // Indicates a store instruction
 reg store_x;
 reg store_m;
 wire [`LM32_SIZE_RNG] size_d;                   // Size of load/store (byte, hword, word)
 reg [`LM32_SIZE_RNG] size_x;
 wire branch_d;                                  // Indicates a branch instruction
 wire branch_predict_d;                          // Indicates a branch is predicted
 wire branch_predict_taken_d;                    // Indicates a branch is predicted taken
 wire [`LM32_PC_RNG] branch_predict_address_d;   // Address to which predicted branch jumps
 wire [`LM32_PC_RNG] branch_target_d;
 wire bi_unconditional;
 wire bi_conditional;
 reg branch_x;
 reg branch_predict_x;
 reg branch_predict_taken_x;
 reg branch_m;
 reg branch_predict_m;
 reg branch_predict_taken_m;
 wire branch_mispredict_taken_m;                 // Indicates a branch was mispredicted as taken
 wire branch_flushX_m;                           // Indicates that instruction in X stage must be squashed
 wire branch_reg_d;                              // Branch to register or immediate
 wire [`LM32_PC_RNG] branch_offset_d;            // Branch offset for immediate branches
 reg [`LM32_PC_RNG] branch_target_x;             // Address to branch to
 reg [`LM32_PC_RNG] branch_target_m;
 wire [`LM32_D_RESULT_SEL_0_RNG] d_result_sel_0_d; // Which result should be selected in D stage for operand 0
 wire [`LM32_D_RESULT_SEL_1_RNG] d_result_sel_1_d; // Which result should be selected in D stage for operand 1
 wire x_result_sel_csr_d;                        // Select X stage result from CSRs
 reg x_result_sel_csr_x;
 `ifdef LM32_MC_ARITHMETIC_ENABLED
 wire x_result_sel_mc_arith_d;                   // Select X stage result from multi-cycle arithmetic unit
 reg x_result_sel_mc_arith_x;
 `endif
 `ifdef LM32_NO_BARREL_SHIFT
 wire x_result_sel_shift_d;                      // Select X stage result from shifter
 reg x_result_sel_shift_x;
 `endif
 `ifdef CFG_SIGN_EXTEND_ENABLED
 wire x_result_sel_sext_d;                       // Select X stage result from sign-extend logic
 reg x_result_sel_sext_x;
 `endif
 wire x_result_sel_logic_d;                      // Select X stage result from logic op unit
 reg x_result_sel_logic_x;
 `ifdef CFG_USER_ENABLED
 wire x_result_sel_user_d;                       // Select X stage result from user-defined logic
 reg x_result_sel_user_x;
 `endif
 wire x_result_sel_add_d;                        // Select X stage result from adder
 reg x_result_sel_add_x;
 wire m_result_sel_compare_d;                    // Select M stage result from comparison logic
 reg m_result_sel_compare_x;
 reg m_result_sel_compare_m;
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
 wire m_result_sel_shift_d;                      // Select M stage result from shifter
 reg m_result_sel_shift_x;
 reg m_result_sel_shift_m;
 `endif
 wire w_result_sel_load_d;                       // Select W stage result from load/store unit
 reg w_result_sel_load_x;
 reg w_result_sel_load_m;
 reg w_result_sel_load_w;
 `ifdef CFG_PL_MULTIPLY_ENABLED
 wire w_result_sel_mul_d;                        // Select W stage result from multiplier
 reg w_result_sel_mul_x;
 reg w_result_sel_mul_m;
 reg w_result_sel_mul_w;
 `endif
 wire x_bypass_enable_d;                         // Whether result is bypassable in X stage
 reg x_bypass_enable_x;
 wire m_bypass_enable_d;                         // Whether result is bypassable in M stage
 reg m_bypass_enable_x;
 reg m_bypass_enable_m;
 wire sign_extend_d;                             // Whether to sign-extend or zero-extend
 reg sign_extend_x;
 wire write_enable_d;                            // Register file write enable
 reg write_enable_x;
 wire write_enable_q_x;
 reg write_enable_m;
 wire write_enable_q_m;
 reg write_enable_w;
 wire write_enable_q_w;
 wire read_enable_0_d;                           // Register file read enable 0
 wire [`LM32_REG_IDX_RNG] read_idx_0_d;          // Register file read index 0
 wire read_enable_1_d;                           // Register file read enable 1
 wire [`LM32_REG_IDX_RNG] read_idx_1_d;          // Register file read index 1
 wire [`LM32_REG_IDX_RNG] write_idx_d;           // Register file write index
 reg [`LM32_REG_IDX_RNG] write_idx_x;
 reg [`LM32_REG_IDX_RNG] write_idx_m;
 reg [`LM32_REG_IDX_RNG] write_idx_w;
 wire [`LM32_CSR_RNG] csr_d;                     // CSR read/write index
 reg  [`LM32_CSR_RNG] csr_x;
 wire [`LM32_CONDITION_RNG] condition_d;         // Branch condition
 reg [`LM32_CONDITION_RNG] condition_x;
 `ifdef CFG_DEBUG_ENABLED
 wire break_d;                                   // Indicates a break instruction
 reg break_x;
 `endif
 wire scall_d;                                   // Indicates a scall instruction
 reg scall_x;
 wire eret_d;                                    // Indicates an eret instruction
 reg eret_x;
 wire eret_q_x;
 reg eret_m;
 `ifdef CFG_TRACE_ENABLED
 reg eret_w;
 `endif
 `ifdef CFG_DEBUG_ENABLED
 wire bret_d;                                    // Indicates a bret instruction
 reg bret_x;
 wire bret_q_x;
 reg bret_m;
 `ifdef CFG_TRACE_ENABLED
 reg bret_w;
 `endif
 `endif
 wire csr_write_enable_d;                        // CSR write enable
 reg csr_write_enable_x;
 wire csr_write_enable_q_x;
 `ifdef CFG_USER_ENABLED
 wire [`LM32_USER_OPCODE_RNG] user_opcode_d;     // User-defined instruction opcode
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
 wire bus_error_d;                               // Indicates an bus error occured while fetching the instruction in this pipeline stage
 reg bus_error_x;
 reg data_bus_error_exception_m;
 reg [`LM32_PC_RNG] memop_pc_w;
 `endif
 reg [`LM32_WORD_RNG] d_result_0;                // Result of instruction in D stage (operand 0)
 reg [`LM32_WORD_RNG] d_result_1;                // Result of instruction in D stage (operand 1)
 reg [`LM32_WORD_RNG] x_result;                  // Result of instruction in X stage
 reg [`LM32_WORD_RNG] m_result;                  // Result of instruction in M stage
 reg [`LM32_WORD_RNG] w_result;                  // Result of instruction in W stage
 reg [`LM32_WORD_RNG] operand_0_x;               // Operand 0 for X stage instruction
 reg [`LM32_WORD_RNG] operand_1_x;               // Operand 1 for X stage instruction
 reg [`LM32_WORD_RNG] store_operand_x;           // Data read from register to store
 reg [`LM32_WORD_RNG] operand_m;                 // Operand for M stage instruction
 reg [`LM32_WORD_RNG] operand_w;                 // Operand for W stage instruction
 // To/from register file
 `ifdef CFG_EBR_POSEDGE_REGISTER_FILE
 reg [`LM32_WORD_RNG] reg_data_live_0;
 reg [`LM32_WORD_RNG] reg_data_live_1;
 reg use_buf;                                    // Whether to use reg_data_live or reg_data_buf
 reg [`LM32_WORD_RNG] reg_data_buf_0;
 reg [`LM32_WORD_RNG] reg_data_buf_1;
 `endif
 `ifdef LM32_EBR_REGISTER_FILE
 `else
 reg [`LM32_WORD_RNG] registers[0:(1<<`LM32_REG_IDX_WIDTH)-1];   // Register file
 `endif
 wire [`LM32_WORD_RNG] reg_data_0;               // Register file read port 0 data
 wire [`LM32_WORD_RNG] reg_data_1;               // Register file read port 1 data
 reg [`LM32_WORD_RNG] bypass_data_0;             // Register value 0 after bypassing
 reg [`LM32_WORD_RNG] bypass_data_1;             // Register value 1 after bypassing
 wire reg_write_enable_q_w;
 reg interlock;                                  // Indicates pipeline should be stalled because of a read-after-write hazzard
 wire stall_a;                                   // Stall instruction in A pipeline stage
 wire stall_f;                                   // Stall instruction in F pipeline stage
 wire stall_d;                                   // Stall instruction in D pipeline stage
 wire stall_x;                                   // Stall instruction in X pipeline stage
 wire stall_m;                                   // Stall instruction in M pipeline stage
 // To/from adder
 wire adder_op_d;                                // Whether to add or subtract
 reg adder_op_x;
 reg adder_op_x_n;                               // Inverted version of adder_op_x
 wire [`LM32_WORD_RNG] adder_result_x;           // Result from adder
 wire adder_overflow_x;                          // Whether a signed overflow occured
 wire adder_carry_n_x;                           // Whether a carry was generated
 // To/from logical operations unit
 wire [`LM32_LOGIC_OP_RNG] logic_op_d;           // Which operation to perform
 reg [`LM32_LOGIC_OP_RNG] logic_op_x;
 wire [`LM32_WORD_RNG] logic_result_x;           // Result of logical operation
 `ifdef CFG_SIGN_EXTEND_ENABLED
 // From sign-extension unit
 wire [`LM32_WORD_RNG] sextb_result_x;           // Result of byte sign-extension
 wire [`LM32_WORD_RNG] sexth_result_x;           // Result of half-word sign-extenstion
 wire [`LM32_WORD_RNG] sext_result_x;            // Result of sign-extension specified by instruction
 `endif
 // To/from shifter
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
 `ifdef CFG_ROTATE_ENABLED
 wire rotate_d;                                  // Whether we should rotate or shift
 reg rotate_x;
 `endif
 wire direction_d;                               // Which direction to shift in
 reg direction_x;
 wire [`LM32_WORD_RNG] shifter_result_m;         // Result of shifter
 `endif
 `ifdef CFG_MC_BARREL_SHIFT_ENABLED
 wire shift_left_d;                              // Indicates whether to perform a left shift or not
 wire shift_left_q_d;
 wire shift_right_d;                             // Indicates whether to perform a right shift or not
 wire shift_right_q_d;
 `endif
 `ifdef LM32_NO_BARREL_SHIFT
 wire [`LM32_WORD_RNG] shifter_result_x;         // Result of single-bit right shifter
 `endif
 // To/from multiplier
 `ifdef LM32_MULTIPLY_ENABLED
 wire [`LM32_WORD_RNG] multiplier_result_w;      // Result from multiplier
 `endif
 `ifdef CFG_MC_MULTIPLY_ENABLED
 wire multiply_d;                                // Indicates whether to perform a multiply or not
 wire multiply_q_d;
 `endif
 // To/from divider
 `ifdef CFG_MC_DIVIDE_ENABLED
 wire divide_d;                                  // Indicates whether to perform a divider or not
 wire divide_q_d;
 wire modulus_d;
 wire modulus_q_d;
 wire divide_by_zero_x;                          // Indicates an attempt was made to divide by zero
 `endif
 // To from multi-cycle arithmetic unit
 `ifdef LM32_MC_ARITHMETIC_ENABLED
 wire mc_stall_request_x;                        // Multi-cycle arithmetic unit stall request
 wire [`LM32_WORD_RNG] mc_result_x;
 `endif
 // From CSRs
 `ifdef CFG_INTERRUPTS_ENABLED
 wire [`LM32_WORD_RNG] interrupt_csr_read_data_x;// Data read from interrupt CSRs
 `endif
 wire [`LM32_WORD_RNG] cfg;                      // Configuration CSR
 wire [`LM32_WORD_RNG] cfg2;                     // Extended Configuration CSR
 `ifdef CFG_CYCLE_COUNTER_ENABLED
 reg [`LM32_WORD_RNG] cc;                        // Cycle counter CSR
 `endif
 reg [`LM32_WORD_RNG] csr_read_data_x;           // Data read from CSRs
 // To/from instruction unit
 wire [`LM32_PC_RNG] pc_f;                       // PC of instruction in F stage
 wire [`LM32_PC_RNG] pc_d;                       // PC of instruction in D stage
 wire [`LM32_PC_RNG] pc_x;                       // PC of instruction in X stage
 wire [`LM32_PC_RNG] pc_m;                       // PC of instruction in M stage
 wire [`LM32_PC_RNG] pc_w;                       // PC of instruction in W stage
 `ifdef CFG_TRACE_ENABLED
 reg [`LM32_PC_RNG] pc_c;                        // PC of last commited instruction
 `endif
 `ifdef CFG_EBR_POSEDGE_REGISTER_FILE
 wire [`LM32_INSTRUCTION_RNG] instruction_f;     // Instruction in F stage
 `endif
 //pragma attribute instruction_d preserve_signal true
 //pragma attribute instruction_d preserve_driver true
 wire [`LM32_INSTRUCTION_RNG] instruction_d;     // Instruction in D stage
 `ifdef CFG_ICACHE_ENABLED
 wire iflush;                                    // Flush instruction cache
 wire icache_stall_request;                      // Stall pipeline because instruction cache is busy
 wire icache_restart_request;                    // Restart instruction that caused an instruction cache miss
 wire icache_refill_request;                     // Request to refill instruction cache
 wire icache_refilling;                          // Indicates the instruction cache is being refilled
 `endif
 `ifdef CFG_IROM_ENABLED
 wire [`LM32_WORD_RNG] irom_store_data_m;        // Store data to instruction ROM
 wire [`LM32_WORD_RNG] irom_address_xm;          // Address to instruction ROM from load-store unit
 wire [`LM32_WORD_RNG] irom_data_m;              // Load data from instruction ROM
 wire irom_we_xm;                                // Indicates data needs to be written to instruction ROM
 wire irom_stall_request_x;                      // Indicates D stage needs to be stalled on a store to instruction ROM
 `endif
 // To/from load/store unit
 `ifdef CFG_DCACHE_ENABLED
 wire dflush_x;                                  // Flush data cache
 reg dflush_m;
 wire dcache_stall_request;                      // Stall pipeline because data cache is busy
 wire dcache_restart_request;                    // Restart instruction that caused a data cache miss
 wire dcache_refill_request;                     // Request to refill data cache
 wire dcache_refilling;                          // Indicates the data cache is being refilled
 `endif
 wire [`LM32_WORD_RNG] load_data_w;              // Result of a load instruction
 wire stall_wb_load;                             // Stall pipeline because of a load via the data Wishbone interface
 // To/from JTAG interface
 `ifdef CFG_JTAG_ENABLED
 `ifdef CFG_JTAG_UART_ENABLED
 wire [`LM32_WORD_RNG] jtx_csr_read_data;        // Read data for JTX CSR
 wire [`LM32_WORD_RNG] jrx_csr_read_data;        // Read data for JRX CSR
 `endif
 `ifdef CFG_HW_DEBUG_ENABLED
 wire jtag_csr_write_enable;                     // Debugger CSR write enable
 wire [`LM32_WORD_RNG] jtag_csr_write_data;      // Data to write to specified CSR
 wire [`LM32_CSR_RNG] jtag_csr;                  // Which CSR to write
 wire jtag_read_enable;
 wire [`LM32_BYTE_RNG] jtag_read_data;
 wire jtag_write_enable;
 wire [`LM32_BYTE_RNG] jtag_write_data;
 wire [`LM32_WORD_RNG] jtag_address;
 wire jtag_access_complete;
 `endif
 `ifdef CFG_DEBUG_ENABLED
 wire jtag_break;                                // Request from debugger to raise a breakpoint
 `endif
 `endif
 // Hazzard detection
 wire raw_x_0;                                   // RAW hazzard between instruction in X stage and read port 0
 wire raw_x_1;                                   // RAW hazzard between instruction in X stage and read port 1
 wire raw_m_0;                                   // RAW hazzard between instruction in M stage and read port 0
 wire raw_m_1;                                   // RAW hazzard between instruction in M stage and read port 1
 wire raw_w_0;                                   // RAW hazzard between instruction in W stage and read port 0
 wire raw_w_1;                                   // RAW hazzard between instruction in W stage and read port 1
 // Control flow
 wire cmp_zero;                                  // Result of comparison is zero
 wire cmp_negative;                              // Result of comparison is negative
 wire cmp_overflow;                              // Comparison produced an overflow
 wire cmp_carry_n;                               // Comparison produced a carry, inverted
 reg condition_met_x;                            // Condition of branch instruction is met
 reg condition_met_m;
 `ifdef CFG_FAST_UNCONDITIONAL_BRANCH
 wire branch_taken_x;                            // Branch is taken in X stage
 `endif
 wire branch_taken_m;                            // Branch is taken in M stage
 wire kill_f;                                    // Kill instruction in F stage
 wire kill_d;                                    // Kill instruction in D stage
 wire kill_x;                                    // Kill instruction in X stage
 wire kill_m;                                    // Kill instruction in M stage
 wire kill_w;                                    // Kill instruction in W stage
 reg [`LM32_PC_WIDTH+2-1:8] eba;                 // Exception Base Address (EBA) CSR
 `ifdef CFG_DEBUG_ENABLED
 reg [`LM32_PC_WIDTH+2-1:8] deba;                // Debug Exception Base Address (DEBA) CSR
 `endif
 reg [`LM32_EID_RNG] eid_x;                      // Exception ID in X stage
 `ifdef CFG_TRACE_ENABLED
 reg [`LM32_EID_RNG] eid_m;                      // Exception ID in M stage
 reg [`LM32_EID_RNG] eid_w;                      // Exception ID in W stage
 `endif
 `ifdef CFG_DEBUG_ENABLED
 `ifdef LM32_SINGLE_STEP_ENABLED
 wire dc_ss;                                     // Is single-step enabled
 `endif
 wire dc_re;                                     // Remap all exceptions
 wire exception_x;                               // An exception occured in the X stage
 reg exception_m;                                // An instruction that caused an exception is in the M stage
 wire debug_exception_x;                         // Indicates if a debug exception has occured
 reg debug_exception_m;
 reg debug_exception_w;
 wire debug_exception_q_w;
 wire non_debug_exception_x;                     // Indicates if a non debug exception has occured
 reg non_debug_exception_m;
 reg non_debug_exception_w;
 wire non_debug_exception_q_w;
 `else
 wire exception_x;                               // Indicates if a debug exception has occured
 reg exception_m;
 reg exception_w;
 wire exception_q_w;
 `endif
 `ifdef CFG_DEBUG_ENABLED
 `ifdef CFG_JTAG_ENABLED
 wire reset_exception;                           // Indicates if a reset exception has occured
 `endif
 `endif
 `ifdef CFG_INTERRUPTS_ENABLED
 wire interrupt_exception;                       // Indicates if an interrupt exception has occured
 `endif
 `ifdef CFG_DEBUG_ENABLED
 wire breakpoint_exception;                      // Indicates if a breakpoint exception has occured
 wire watchpoint_exception;                      // Indicates if a watchpoint exception has occured
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
 wire instruction_bus_error_exception;           // Indicates if an instruction bus error exception has occured
 wire data_bus_error_exception;                  // Indicates if a data bus error exception has occured
 `endif
 `ifdef CFG_MC_DIVIDE_ENABLED
 wire divide_by_zero_exception;                  // Indicates if a divide by zero exception has occured
 `endif
 wire system_call_exception;                     // Indicates if a system call exception has occured
 `ifdef CFG_BUS_ERRORS_ENABLED
 reg data_bus_error_seen;                        // Indicates if a data bus error was seen
 `endif
 /////////////////////////////////////////////////////
 // Functions
 /////////////////////////////////////////////////////
 `include "lm32_functions.v"
 /////////////////////////////////////////////////////
 // Instantiations
 /////////////////////////////////////////////////////
 // Instruction unit
 lm32_instruction_unit #(
     .associativity          (icache_associativity),
     .sets                   (icache_sets),
     .bytes_per_line         (icache_bytes_per_line),
     .base_address           (icache_base_address),
     .limit                  (icache_limit)
   ) instruction_unit (
     // ----- Inputs -------
     .clk_i                  (clk_i),
     .rst_i                  (rst_i),
 `ifdef CFG_DEBUG_ENABLED
  `ifdef CFG_ALTERNATE_EBA
     .at_debug               (at_debug),
  `endif
 `endif
     // From pipeline
     .stall_a                (stall_a),
     .stall_f                (stall_f),
     .stall_d                (stall_d),
     .stall_x                (stall_x),
     .stall_m                (stall_m),
     .valid_f                (valid_f),
     .valid_d                (valid_d),
     .kill_f                 (kill_f),
     .branch_predict_taken_d (branch_predict_taken_d),
     .branch_predict_address_d (branch_predict_address_d),
 `ifdef CFG_FAST_UNCONDITIONAL_BRANCH
     .branch_taken_x         (branch_taken_x),
     .branch_target_x        (branch_target_x),
 `endif
     .exception_m            (exception_m),
     .branch_taken_m         (branch_taken_m),
     .branch_mispredict_taken_m (branch_mispredict_taken_m),
     .branch_target_m        (branch_target_m),
 `ifdef CFG_ICACHE_ENABLED
     .iflush                 (iflush),
 `endif
 `ifdef CFG_IROM_ENABLED
     .irom_store_data_m      (irom_store_data_m),
     .irom_address_xm        (irom_address_xm),
     .irom_we_xm             (irom_we_xm),
 `endif
 `ifdef CFG_DCACHE_ENABLED
     .dcache_restart_request (dcache_restart_request),
     .dcache_refill_request  (dcache_refill_request),
     .dcache_refilling       (dcache_refilling),
 `endif
 `ifdef CFG_IWB_ENABLED
     // From Wishbone
     .i_dat_i                (I_DAT_I),
     .i_ack_i                (I_ACK_I),
     .i_err_i                (I_ERR_I),
 `endif
 `ifdef CFG_HW_DEBUG_ENABLED
     .jtag_read_enable       (jtag_read_enable),
     .jtag_write_enable      (jtag_write_enable),
     .jtag_write_data        (jtag_write_data),
     .jtag_address           (jtag_address),
 `endif
     // ----- Outputs -------
     // To pipeline
     .pc_f                   (pc_f),
     .pc_d                   (pc_d),
     .pc_x                   (pc_x),
     .pc_m                   (pc_m),
     .pc_w                   (pc_w),
 `ifdef CFG_ICACHE_ENABLED
     .icache_stall_request   (icache_stall_request),
     .icache_restart_request (icache_restart_request),
     .icache_refill_request  (icache_refill_request),
     .icache_refilling       (icache_refilling),
 `endif
 `ifdef CFG_IROM_ENABLED
     .irom_data_m            (irom_data_m),
 `endif
 `ifdef CFG_IWB_ENABLED
     // To Wishbone
     .i_dat_o                (I_DAT_O),
     .i_adr_o                (I_ADR_O),
     .i_cyc_o                (I_CYC_O),
     .i_sel_o                (I_SEL_O),
     .i_stb_o                (I_STB_O),
     .i_we_o                 (I_WE_O),
     .i_cti_o                (I_CTI_O),
     .i_lock_o               (I_LOCK_O),
     .i_bte_o                (I_BTE_O),
 `endif
 `ifdef CFG_HW_DEBUG_ENABLED
     .jtag_read_data         (jtag_read_data),
     .jtag_access_complete   (jtag_access_complete),
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
     .bus_error_d            (bus_error_d),
 `endif
 `ifdef CFG_EBR_POSEDGE_REGISTER_FILE
     .instruction_f          (instruction_f),
 `endif
     .instruction_d          (instruction_d)
     );
 // Instruction decoder
 lm32_decoder decoder (
     // ----- Inputs -------
     .instruction            (instruction_d),
     // ----- Outputs -------
     .d_result_sel_0         (d_result_sel_0_d),
     .d_result_sel_1         (d_result_sel_1_d),
     .x_result_sel_csr       (x_result_sel_csr_d),
 `ifdef LM32_MC_ARITHMETIC_ENABLED
     .x_result_sel_mc_arith  (x_result_sel_mc_arith_d),
 `endif
 `ifdef LM32_NO_BARREL_SHIFT
     .x_result_sel_shift     (x_result_sel_shift_d),
 `endif
 `ifdef CFG_SIGN_EXTEND_ENABLED
     .x_result_sel_sext      (x_result_sel_sext_d),
 `endif
     .x_result_sel_logic     (x_result_sel_logic_d),
 `ifdef CFG_USER_ENABLED
     .x_result_sel_user      (x_result_sel_user_d),
 `endif
     .x_result_sel_add       (x_result_sel_add_d),
     .m_result_sel_compare   (m_result_sel_compare_d),
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
     .m_result_sel_shift     (m_result_sel_shift_d),
 `endif
     .w_result_sel_load      (w_result_sel_load_d),
 `ifdef CFG_PL_MULTIPLY_ENABLED
     .w_result_sel_mul       (w_result_sel_mul_d),
 `endif
     .x_bypass_enable        (x_bypass_enable_d),
     .m_bypass_enable        (m_bypass_enable_d),
     .read_enable_0          (read_enable_0_d),
     .read_idx_0             (read_idx_0_d),
     .read_enable_1          (read_enable_1_d),
     .read_idx_1             (read_idx_1_d),
     .write_enable           (write_enable_d),
     .write_idx              (write_idx_d),
     .immediate              (immediate_d),
     .branch_offset          (branch_offset_d),
     .load                   (load_d),
     .store                  (store_d),
     .size                   (size_d),
     .sign_extend            (sign_extend_d),
     .adder_op               (adder_op_d),
     .logic_op               (logic_op_d),
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
     .direction              (direction_d),
 `endif
 `ifdef CFG_MC_BARREL_SHIFT_ENABLED
     .shift_left             (shift_left_d),
     .shift_right            (shift_right_d),
 `endif
 `ifdef CFG_MC_MULTIPLY_ENABLED
     .multiply               (multiply_d),
 `endif
 `ifdef CFG_MC_DIVIDE_ENABLED
     .divide                 (divide_d),
     .modulus                (modulus_d),
 `endif
     .branch                 (branch_d),
     .bi_unconditional       (bi_unconditional),
     .bi_conditional         (bi_conditional),
     .branch_reg             (branch_reg_d),
     .condition              (condition_d),
 `ifdef CFG_DEBUG_ENABLED
     .break_opcode           (break_d),
 `endif
     .scall                  (scall_d),
     .eret                   (eret_d),
 `ifdef CFG_DEBUG_ENABLED
     .bret                   (bret_d),
 `endif
 `ifdef CFG_USER_ENABLED
     .user_opcode            (user_opcode_d),
 `endif
     .csr_write_enable       (csr_write_enable_d)
     );
 // Load/store unit
 lm32_load_store_unit #(
     .associativity          (dcache_associativity),
     .sets                   (dcache_sets),
     .bytes_per_line         (dcache_bytes_per_line),
     .base_address           (dcache_base_address),
     .limit                  (dcache_limit)
   ) load_store_unit (
     // ----- Inputs -------
     .clk_i                  (clk_i),
     .rst_i                  (rst_i),
     // From pipeline
     .stall_a                (stall_a),
     .stall_x                (stall_x),
     .stall_m                (stall_m),
     .kill_m                 (kill_m),
     .exception_m            (exception_m),
     .store_operand_x        (store_operand_x),
     .load_store_address_x   (adder_result_x),
     .load_store_address_m   (operand_m),
     .load_store_address_w   (operand_w[1:0]),
     .load_x                 (load_x),
     .store_x                (store_x),
     .load_q_x               (load_q_x),
     .store_q_x              (store_q_x),
     .load_q_m               (load_q_m),
     .store_q_m              (store_q_m),
     .sign_extend_x          (sign_extend_x),
     .size_x                 (size_x),
 `ifdef CFG_DCACHE_ENABLED
     .dflush                 (dflush_m),
 `endif
 `ifdef CFG_IROM_ENABLED
     .irom_data_m            (irom_data_m),
 `endif
     // From Wishbone
     .d_dat_i                (D_DAT_I),
     .d_ack_i                (D_ACK_I),
     .d_err_i                (D_ERR_I),
     .d_rty_i                (D_RTY_I),
     // ----- Outputs -------
     // To pipeline
 `ifdef CFG_DCACHE_ENABLED
     .dcache_refill_request  (dcache_refill_request),
     .dcache_restart_request (dcache_restart_request),
     .dcache_stall_request   (dcache_stall_request),
     .dcache_refilling       (dcache_refilling),
 `endif
 `ifdef CFG_IROM_ENABLED
     .irom_store_data_m      (irom_store_data_m),
     .irom_address_xm        (irom_address_xm),
     .irom_we_xm             (irom_we_xm),
     .irom_stall_request_x   (irom_stall_request_x),
 `endif
     .load_data_w            (load_data_w),
     .stall_wb_load          (stall_wb_load),
     // To Wishbone
     .d_dat_o                (D_DAT_O),
     .d_adr_o                (D_ADR_O),
     .d_cyc_o                (D_CYC_O),
     .d_sel_o                (D_SEL_O),
     .d_stb_o                (D_STB_O),
     .d_we_o                 (D_WE_O),
     .d_cti_o                (D_CTI_O),
     .d_lock_o               (D_LOCK_O),
     .d_bte_o                (D_BTE_O)
     );
 // Adder
 lm32_adder adder (
     // ----- Inputs -------
     .adder_op_x             (adder_op_x),
     .adder_op_x_n           (adder_op_x_n),
     .operand_0_x            (operand_0_x),
     .operand_1_x            (operand_1_x),
     // ----- Outputs -------
     .adder_result_x         (adder_result_x),
     .adder_carry_n_x        (adder_carry_n_x),
     .adder_overflow_x       (adder_overflow_x)
     );
 // Logic operations
 lm32_logic_op logic_op (
     // ----- Inputs -------
     .logic_op_x             (logic_op_x),
     .operand_0_x            (operand_0_x),
     .operand_1_x            (operand_1_x),
     // ----- Outputs -------
     .logic_result_x         (logic_result_x)
     );
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
 // Pipelined barrel-shifter
 lm32_shifter shifter (
     // ----- Inputs -------
     .clk_i                  (clk_i),
     .rst_i                  (rst_i),
     .stall_x                (stall_x),
     .direction_x            (direction_x),
     .sign_extend_x          (sign_extend_x),
     .operand_0_x            (operand_0_x),
     .operand_1_x            (operand_1_x),
     // ----- Outputs -------
     .shifter_result_m       (shifter_result_m)
     );
 `endif
 `ifdef CFG_PL_MULTIPLY_ENABLED
 // Pipeline fixed-point multiplier
 lm32_multiplier multiplier (
     // ----- Inputs -------
     .clk_i                  (clk_i),
     .rst_i                  (rst_i),
     .stall_x                (stall_x),
     .stall_m                (stall_m),
     .operand_0              (d_result_0),
     .operand_1              (d_result_1),
     // ----- Outputs -------
     .result                 (multiplier_result_w)
     );
 `endif
 `ifdef LM32_MC_ARITHMETIC_ENABLED
 // Multi-cycle arithmetic
 lm32_mc_arithmetic mc_arithmetic (
     // ----- Inputs -------
     .clk_i                  (clk_i),
     .rst_i                  (rst_i),
     .stall_d                (stall_d),
     .kill_x                 (kill_x),
 `ifdef CFG_MC_DIVIDE_ENABLED
     .divide_d               (divide_q_d),
     .modulus_d              (modulus_q_d),
 `endif
 `ifdef CFG_MC_MULTIPLY_ENABLED
     .multiply_d             (multiply_q_d),
 `endif
 `ifdef CFG_MC_BARREL_SHIFT_ENABLED
     .shift_left_d           (shift_left_q_d),
     .shift_right_d          (shift_right_q_d),
     .sign_extend_d          (sign_extend_d),
 `endif
     .operand_0_d            (d_result_0),
     .operand_1_d            (d_result_1),
     // ----- Outputs -------
     .result_x               (mc_result_x),
 `ifdef CFG_MC_DIVIDE_ENABLED
     .divide_by_zero_x       (divide_by_zero_x),
 `endif
     .stall_request_x        (mc_stall_request_x)
     );
 `endif
 `ifdef CFG_INTERRUPTS_ENABLED
 // Interrupt unit
 lm32_interrupt interrupt (
     // ----- Inputs -------
     .clk_i                  (clk_i),
     .rst_i                  (rst_i),
     // From external devices
     .interrupt_n            (interrupt_n),
     // From pipeline
     .stall_x                (stall_x),
 `ifdef CFG_DEBUG_ENABLED
     .non_debug_exception    (non_debug_exception_q_w),
     .debug_exception        (debug_exception_q_w),
 `else
     .exception              (exception_q_w),
 `endif
     .eret_q_x               (eret_q_x),
 `ifdef CFG_DEBUG_ENABLED
     .bret_q_x               (bret_q_x),
 `endif
     .csr                    (csr_x),
     .csr_write_data         (operand_1_x),
     .csr_write_enable       (csr_write_enable_q_x),
     // ----- Outputs -------
     .interrupt_exception    (interrupt_exception),
     // To pipeline
     .csr_read_data          (interrupt_csr_read_data_x)
     );
 `endif
 `ifdef CFG_JTAG_ENABLED
 // JTAG interface
 lm32_jtag jtag (
     // ----- Inputs -------
     .clk_i                  (clk_i),
     .rst_i                  (rst_i),
     // From JTAG
     .jtag_clk               (jtag_clk),
     .jtag_update            (jtag_update),
     .jtag_reg_q             (jtag_reg_q),
     .jtag_reg_addr_q        (jtag_reg_addr_q),
     // From pipeline
 `ifdef CFG_JTAG_UART_ENABLED
     .csr                    (csr_x),
     .csr_write_data         (operand_1_x),
     .csr_write_enable       (csr_write_enable_q_x),
     .stall_x                (stall_x),
 `endif
 `ifdef CFG_HW_DEBUG_ENABLED
     .jtag_read_data         (jtag_read_data),
     .jtag_access_complete   (jtag_access_complete),
 `endif
 `ifdef CFG_DEBUG_ENABLED
     .exception_q_w          (debug_exception_q_w || non_debug_exception_q_w),
 `endif
     // ----- Outputs -------
     // To pipeline
 `ifdef CFG_JTAG_UART_ENABLED
     .jtx_csr_read_data      (jtx_csr_read_data),
     .jrx_csr_read_data      (jrx_csr_read_data),
 `endif
 `ifdef CFG_HW_DEBUG_ENABLED
     .jtag_csr_write_enable  (jtag_csr_write_enable),
     .jtag_csr_write_data    (jtag_csr_write_data),
     .jtag_csr               (jtag_csr),
     .jtag_read_enable       (jtag_read_enable),
     .jtag_write_enable      (jtag_write_enable),
     .jtag_write_data        (jtag_write_data),
     .jtag_address           (jtag_address),
 `endif
 `ifdef CFG_DEBUG_ENABLED
     .jtag_break             (jtag_break),
     .jtag_reset             (reset_exception),
 `endif
     // To JTAG
     .jtag_reg_d             (jtag_reg_d),
     .jtag_reg_addr_d        (jtag_reg_addr_d)
     );
 `endif
 `ifdef CFG_DEBUG_ENABLED
 // Debug unit
 lm32_debug #(
     .breakpoints            (breakpoints),
     .watchpoints            (watchpoints)
   ) hw_debug (
     // ----- Inputs -------
     .clk_i                  (clk_i),
     .rst_i                  (rst_i),
     .pc_x                   (pc_x),
     .load_x                 (load_x),
     .store_x                (store_x),
     .load_store_address_x   (adder_result_x),
     .csr_write_enable_x     (csr_write_enable_q_x),
     .csr_write_data         (operand_1_x),
     .csr_x                  (csr_x),
 `ifdef CFG_HW_DEBUG_ENABLED
     .jtag_csr_write_enable  (jtag_csr_write_enable),
     .jtag_csr_write_data    (jtag_csr_write_data),
     .jtag_csr               (jtag_csr),
 `endif
 `ifdef LM32_SINGLE_STEP_ENABLED
     .eret_q_x               (eret_q_x),
     .bret_q_x               (bret_q_x),
     .stall_x                (stall_x),
     .exception_x            (exception_x),
     .q_x                    (q_x),
 `ifdef CFG_DCACHE_ENABLED
     .dcache_refill_request  (dcache_refill_request),
 `endif
 `endif
     // ----- Outputs -------
 `ifdef LM32_SINGLE_STEP_ENABLED
     .dc_ss                  (dc_ss),
 `endif
     .dc_re                  (dc_re),
     .bp_match               (bp_match),
     .wp_match               (wp_match)
     );
 `endif
 // Register file
 `ifdef CFG_EBR_POSEDGE_REGISTER_FILE
    /*----------------------------------------------------------------------
     Register File is implemented using EBRs. There can be three accesses to
     the register file in each cycle: two reads and one write. On-chip block
     RAM has two read/write ports. To accomodate three accesses, two on-chip
     block RAMs are used (each register file "write" is made to both block
     RAMs).
     One limitation of the on-chip block RAMs is that one cannot perform a
     read and write to same location in a cycle (if this is done, then the
     data read out is indeterminate).
     ----------------------------------------------------------------------*/
    wire [31:0] regfile_data_0, regfile_data_1;
    reg [31:0]  w_result_d;
    reg 	       regfile_raw_0, regfile_raw_0_nxt;
    reg 	       regfile_raw_1, regfile_raw_1_nxt;
    /*----------------------------------------------------------------------
     Check if read and write is being performed to same register in current
     cycle? This is done by comparing the read and write IDXs.
     ----------------------------------------------------------------------*/
    always @(reg_write_enable_q_w or write_idx_w or instruction_f)
      begin
 	if (reg_write_enable_q_w
 	    && (write_idx_w == instruction_f[25:21]))
 	  regfile_raw_0_nxt = 1'b1;
 	else
 	  regfile_raw_0_nxt = 1'b0;
 	if (reg_write_enable_q_w
 	    && (write_idx_w == instruction_f[20:16]))
 	  regfile_raw_1_nxt = 1'b1;
 	else
 	  regfile_raw_1_nxt = 1'b0;
      end
    /*----------------------------------------------------------------------
     Select latched (delayed) write value or data from register file. If
     read in previous cycle was performed to register written to in same
     cycle, then latched (delayed) write value is selected.
     ----------------------------------------------------------------------*/
    always @(regfile_raw_0 or w_result_d or regfile_data_0)
      if (regfile_raw_0)
        reg_data_live_0 = w_result_d;
      else
        reg_data_live_0 = regfile_data_0;
    /*----------------------------------------------------------------------
     Select latched (delayed) write value or data from register file. If
     read in previous cycle was performed to register written to in same
     cycle, then latched (delayed) write value is selected.
     ----------------------------------------------------------------------*/
    always @(regfile_raw_1 or w_result_d or regfile_data_1)
      if (regfile_raw_1)
        reg_data_live_1 = w_result_d;
      else
        reg_data_live_1 = regfile_data_1;
    /*----------------------------------------------------------------------
     Latch value written to register file
     ----------------------------------------------------------------------*/
    always @(posedge clk_i `CFG_RESET_SENSITIVITY)
      if (rst_i == `TRUE)
        begin
 	  regfile_raw_0 <= #1 1'b0;
 	  regfile_raw_1 <= #1 1'b0;
 	  w_result_d <= #1 32'b0;
        end
      else
        begin
 	  regfile_raw_0 <= #1 regfile_raw_0_nxt;
 	  regfile_raw_1 <= #1 regfile_raw_1_nxt;
 	  w_result_d <= #1 w_result;
        end
    /*----------------------------------------------------------------------
     Register file instantiation as Pseudo-Dual Port EBRs.
     ----------------------------------------------------------------------*/
    pmi_ram_dp
      #(
        // ----- Parameters -----
        .pmi_wr_addr_depth(1<<5),
        .pmi_wr_addr_width(5),
        .pmi_wr_data_width(32),
        .pmi_rd_addr_depth(1<<5),
        .pmi_rd_addr_width(5),
        .pmi_rd_data_width(32),
        .pmi_regmode("noreg"),
        .pmi_gsr("enable"),
        .pmi_resetmode("sync"),
        .pmi_init_file("none"),
        .pmi_init_file_format("binary"),
        .pmi_family(`LATTICE_FAMILY),
        .module_type("pmi_ram_dp")
        )
    reg_0
      (
       // ----- Inputs -----
       .Data(w_result),
       .WrAddress(write_idx_w),
       .RdAddress(instruction_f[25:21]),
       .WrClock(clk_i),
       .RdClock(clk_i),
       .WrClockEn(`TRUE),
       .RdClockEn(`TRUE),
       .WE(reg_write_enable_q_w),
       .Reset(rst_i),
       // ----- Outputs -----
       .Q(regfile_data_0)
       );
    pmi_ram_dp
      #(
        // ----- Parameters -----
        .pmi_wr_addr_depth(1<<5),
        .pmi_wr_addr_width(5),
        .pmi_wr_data_width(32),
        .pmi_rd_addr_depth(1<<5),
        .pmi_rd_addr_width(5),
        .pmi_rd_data_width(32),
        .pmi_regmode("noreg"),
        .pmi_gsr("enable"),
        .pmi_resetmode("sync"),
        .pmi_init_file("none"),
        .pmi_init_file_format("binary"),
        .pmi_family(`LATTICE_FAMILY),
        .module_type("pmi_ram_dp")
        )
    reg_1
      (
       // ----- Inputs -----
       .Data(w_result),
       .WrAddress(write_idx_w),
       .RdAddress(instruction_f[20:16]),
       .WrClock(clk_i),
       .RdClock(clk_i),
       .WrClockEn(`TRUE),
       .RdClockEn(`TRUE),
       .WE(reg_write_enable_q_w),
       .Reset(rst_i),
       // ----- Outputs -----
       .Q(regfile_data_1)
       );
 `endif
 `ifdef CFG_EBR_NEGEDGE_REGISTER_FILE
    pmi_ram_dp
      #(
        // ----- Parameters -----
        .pmi_wr_addr_depth(1<<5),
        .pmi_wr_addr_width(5),
        .pmi_wr_data_width(32),
        .pmi_rd_addr_depth(1<<5),
        .pmi_rd_addr_width(5),
        .pmi_rd_data_width(32),
        .pmi_regmode("noreg"),
        .pmi_gsr("enable"),
        .pmi_resetmode("sync"),
        .pmi_init_file("none"),
        .pmi_init_file_format("binary"),
        .pmi_family(`LATTICE_FAMILY),
        .module_type("pmi_ram_dp")
        )
    reg_0
      (
       // ----- Inputs -----
       .Data(w_result),
       .WrAddress(write_idx_w),
       .RdAddress(read_idx_0_d),
       .WrClock(clk_i),
       .RdClock(clk_n_i),
       .WrClockEn(`TRUE),
       .RdClockEn(stall_f == `FALSE),
       .WE(reg_write_enable_q_w),
       .Reset(rst_i),
       // ----- Outputs -----
       .Q(reg_data_0)
       );
    pmi_ram_dp
      #(
        // ----- Parameters -----
        .pmi_wr_addr_depth(1<<5),
        .pmi_wr_addr_width(5),
        .pmi_wr_data_width(32),
        .pmi_rd_addr_depth(1<<5),
        .pmi_rd_addr_width(5),
        .pmi_rd_data_width(32),
        .pmi_regmode("noreg"),
        .pmi_gsr("enable"),
        .pmi_resetmode("sync"),
        .pmi_init_file("none"),
        .pmi_init_file_format("binary"),
        .pmi_family(`LATTICE_FAMILY),
        .module_type("pmi_ram_dp")
        )
    reg_1
      (
       // ----- Inputs -----
       .Data(w_result),
       .WrAddress(write_idx_w),
       .RdAddress(read_idx_1_d),
       .WrClock(clk_i),
       .RdClock(clk_n_i),
       .WrClockEn(`TRUE),
       .RdClockEn(stall_f == `FALSE),
       .WE(reg_write_enable_q_w),
       .Reset(rst_i),
       // ----- Outputs -----
       .Q(reg_data_1)
       );
 `endif
 /////////////////////////////////////////////////////
 // Combinational Logic
 /////////////////////////////////////////////////////
 `ifdef CFG_EBR_POSEDGE_REGISTER_FILE
 // Select between buffered and live data from register file
 assign reg_data_0 = use_buf ? reg_data_buf_0 : reg_data_live_0;
 assign reg_data_1 = use_buf ? reg_data_buf_1 : reg_data_live_1;
 `endif
 `ifdef LM32_EBR_REGISTER_FILE
 `else
 // Register file read ports
 assign reg_data_0 = registers[read_idx_0_d];
 assign reg_data_1 = registers[read_idx_1_d];
 `endif
 // Detect read-after-write hazzards
 assign raw_x_0 = (write_idx_x == read_idx_0_d) && (write_enable_q_x == `TRUE);
 assign raw_m_0 = (write_idx_m == read_idx_0_d) && (write_enable_q_m == `TRUE);
 assign raw_w_0 = (write_idx_w == read_idx_0_d) && (write_enable_q_w == `TRUE);
 assign raw_x_1 = (write_idx_x == read_idx_1_d) && (write_enable_q_x == `TRUE);
 assign raw_m_1 = (write_idx_m == read_idx_1_d) && (write_enable_q_m == `TRUE);
 assign raw_w_1 = (write_idx_w == read_idx_1_d) && (write_enable_q_w == `TRUE);
 // Interlock detection - Raise an interlock for RAW hazzards
 always @(*)
 begin
     if (   (   (x_bypass_enable_x == `FALSE)
             && (   ((read_enable_0_d == `TRUE) && (raw_x_0 == `TRUE))
                 || ((read_enable_1_d == `TRUE) && (raw_x_1 == `TRUE))
                )
            )
         || (   (m_bypass_enable_m == `FALSE)
             && (   ((read_enable_0_d == `TRUE) && (raw_m_0 == `TRUE))
                 || ((read_enable_1_d == `TRUE) && (raw_m_1 == `TRUE))
                )
            )
        )
         interlock = `TRUE;
     else
         interlock = `FALSE;
 end
 // Bypass for reg port 0
 always @(*)
 begin
     if (raw_x_0 == `TRUE)
         bypass_data_0 = x_result;
     else if (raw_m_0 == `TRUE)
         bypass_data_0 = m_result;
     else if (raw_w_0 == `TRUE)
         bypass_data_0 = w_result;
     else
         bypass_data_0 = reg_data_0;
 end
 // Bypass for reg port 1
 always @(*)
 begin
     if (raw_x_1 == `TRUE)
         bypass_data_1 = x_result;
     else if (raw_m_1 == `TRUE)
         bypass_data_1 = m_result;
     else if (raw_w_1 == `TRUE)
         bypass_data_1 = w_result;
     else
         bypass_data_1 = reg_data_1;
 end
    /*----------------------------------------------------------------------
     Branch prediction is performed in D stage of pipeline. Only PC-relative
     branches are predicted: forward-pointing conditional branches are not-
     taken, while backward-pointing conditional branches are taken.
     Unconditional branches are always predicted taken!
     ----------------------------------------------------------------------*/
    assign branch_predict_d = bi_unconditional | bi_conditional;
    assign branch_predict_taken_d = bi_unconditional ? 1'b1 : (bi_conditional ? instruction_d[15] : 1'b0);
    // Compute branch target address: Branch PC PLUS Offset
    assign branch_target_d = pc_d + branch_offset_d;
    // Compute fetch address. Address of instruction sequentially after the
    // branch if branch is not taken. Target address of branch is branch is
    // taken
    assign branch_predict_address_d = branch_predict_taken_d ? branch_target_d : pc_f;
 // D stage result selection
 always @(*)
 begin
     d_result_0 = d_result_sel_0_d[0] ? {pc_f, 2'b00} : bypass_data_0;
     case (d_result_sel_1_d)
     `LM32_D_RESULT_SEL_1_ZERO:      d_result_1 = {`LM32_WORD_WIDTH{1'b0}};
     `LM32_D_RESULT_SEL_1_REG_1:     d_result_1 = bypass_data_1;
     `LM32_D_RESULT_SEL_1_IMMEDIATE: d_result_1 = immediate_d;
     default:                        d_result_1 = {`LM32_WORD_WIDTH{1'bx}};
     endcase
 end
 `ifdef CFG_USER_ENABLED
 // Operands for user-defined instructions
 assign user_operand_0 = operand_0_x;
 assign user_operand_1 = operand_1_x;
 `endif
 `ifdef CFG_SIGN_EXTEND_ENABLED
 // Sign-extension
 assign sextb_result_x = {{24{operand_0_x[7]}}, operand_0_x[7:0]};
 assign sexth_result_x = {{16{operand_0_x[15]}}, operand_0_x[15:0]};
 assign sext_result_x = size_x == `LM32_SIZE_BYTE ? sextb_result_x : sexth_result_x;
 `endif
 `ifdef LM32_NO_BARREL_SHIFT
 // Only single bit shift operations are supported when barrel-shifter isn't implemented
 assign shifter_result_x = {operand_0_x[`LM32_WORD_WIDTH-1] & sign_extend_x, operand_0_x[`LM32_WORD_WIDTH-1:1]};
 `endif
 // Condition evaluation
 assign cmp_zero = operand_0_x == operand_1_x;
 assign cmp_negative = adder_result_x[`LM32_WORD_WIDTH-1];
 assign cmp_overflow = adder_overflow_x;
 assign cmp_carry_n = adder_carry_n_x;
 always @(*)
 begin
     case (condition_x)
     `LM32_CONDITION_U1:   condition_met_x = `TRUE;
     `LM32_CONDITION_U2:   condition_met_x = `TRUE;
     `LM32_CONDITION_E:    condition_met_x = cmp_zero;
     `LM32_CONDITION_NE:   condition_met_x = !cmp_zero;
     `LM32_CONDITION_G:    condition_met_x = !cmp_zero && (cmp_negative == cmp_overflow);
     `LM32_CONDITION_GU:   condition_met_x = cmp_carry_n && !cmp_zero;
     `LM32_CONDITION_GE:   condition_met_x = cmp_negative == cmp_overflow;
     `LM32_CONDITION_GEU:  condition_met_x = cmp_carry_n;
     default:              condition_met_x = 1'bx;
     endcase
 end
 // X stage result selection
 always @(*)
 begin
     x_result =   x_result_sel_add_x ? adder_result_x
                : x_result_sel_csr_x ? csr_read_data_x
 `ifdef CFG_SIGN_EXTEND_ENABLED
                : x_result_sel_sext_x ? sext_result_x
 `endif
 `ifdef CFG_USER_ENABLED
                : x_result_sel_user_x ? user_result
 `endif
 `ifdef LM32_NO_BARREL_SHIFT
                : x_result_sel_shift_x ? shifter_result_x
 `endif
 `ifdef LM32_MC_ARITHMETIC_ENABLED
                : x_result_sel_mc_arith_x ? mc_result_x
 `endif
                : logic_result_x;
 end
 // M stage result selection
 always @(*)
 begin
     m_result =   m_result_sel_compare_m ? {{`LM32_WORD_WIDTH-1{1'b0}}, condition_met_m}
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
                : m_result_sel_shift_m ? shifter_result_m
 `endif
                : operand_m;
 end
 // W stage result selection
 always @(*)
 begin
     w_result =    w_result_sel_load_w ? load_data_w
 `ifdef CFG_PL_MULTIPLY_ENABLED
                 : w_result_sel_mul_w ? multiplier_result_w
 `endif
                 : operand_w;
 end
 `ifdef CFG_FAST_UNCONDITIONAL_BRANCH
 // Indicate when a branch should be taken in X stage
 assign branch_taken_x =      (stall_x == `FALSE)
                           && (   (branch_x == `TRUE)
                               && ((condition_x == `LM32_CONDITION_U1) || (condition_x == `LM32_CONDITION_U2))
                               && (valid_x == `TRUE)
                               && (branch_predict_x == `FALSE)
                              );
 `endif
 // Indicate when a branch should be taken in M stage (exceptions are a type of branch)
 assign branch_taken_m =      (stall_m == `FALSE)
                           && (   (   (branch_m == `TRUE)
                                   && (valid_m == `TRUE)
                                   && (   (   (condition_met_m == `TRUE)
 					  && (branch_predict_taken_m == `FALSE)
 					 )
 				      || (   (condition_met_m == `FALSE)
 					  && (branch_predict_m == `TRUE)
 					  && (branch_predict_taken_m == `TRUE)
 					 )
 				     )
                                  )
                               || (exception_m == `TRUE)
                              );
 // Indicate when a branch in M stage is mispredicted as being taken
 assign branch_mispredict_taken_m =    (condition_met_m == `FALSE)
                                    && (branch_predict_m == `TRUE)
 	   			   && (branch_predict_taken_m == `TRUE);
 // Indicate when a branch in M stage will cause flush in X stage
 assign branch_flushX_m =    (stall_m == `FALSE)
                          && (   (   (branch_m == `TRUE)
                                  && (valid_m == `TRUE)
 			         && (   (condition_met_m == `TRUE)
 				     || (   (condition_met_m == `FALSE)
 					 && (branch_predict_m == `TRUE)
 					 && (branch_predict_taken_m == `TRUE)
 					)
 				    )
 			        )
 			     || (exception_m == `TRUE)
 			    );
 // Generate signal that will kill instructions in each pipeline stage when necessary
 assign kill_f =    (   (valid_d == `TRUE)
                     && (branch_predict_taken_d == `TRUE)
 		   )
                 || (branch_taken_m == `TRUE)
 `ifdef CFG_FAST_UNCONDITIONAL_BRANCH
                 || (branch_taken_x == `TRUE)
 `endif
 `ifdef CFG_ICACHE_ENABLED
                 || (icache_refill_request == `TRUE)
 `endif
 `ifdef CFG_DCACHE_ENABLED
                 || (dcache_refill_request == `TRUE)
 `endif
                 ;
 assign kill_d =    (branch_taken_m == `TRUE)
 `ifdef CFG_FAST_UNCONDITIONAL_BRANCH
                 || (branch_taken_x == `TRUE)
 `endif
 `ifdef CFG_ICACHE_ENABLED
                 || (icache_refill_request == `TRUE)
 `endif
 `ifdef CFG_DCACHE_ENABLED
                 || (dcache_refill_request == `TRUE)
 `endif
                 ;
 assign kill_x =    (branch_flushX_m == `TRUE)
 `ifdef CFG_DCACHE_ENABLED
                 || (dcache_refill_request == `TRUE)
 `endif
                 ;
 assign kill_m =    `FALSE
 `ifdef CFG_DCACHE_ENABLED
                 || (dcache_refill_request == `TRUE)
 `endif
                 ;
 assign kill_w =    `FALSE
 `ifdef CFG_DCACHE_ENABLED
                 || (dcache_refill_request == `TRUE)
 `endif
                 ;
 // Exceptions
 `ifdef CFG_DEBUG_ENABLED
 assign breakpoint_exception =    (   (   (break_x == `TRUE)
 				      || (bp_match == `TRUE)
 				     )
 				  && (valid_x == `TRUE)
 				 )
 `ifdef CFG_JTAG_ENABLED
                               || (jtag_break == `TRUE)
 `endif
                               ;
 `endif
 `ifdef CFG_DEBUG_ENABLED
 assign watchpoint_exception = wp_match == `TRUE;
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
 assign instruction_bus_error_exception = (   (bus_error_x == `TRUE)
                                           && (valid_x == `TRUE)
                                          );
 assign data_bus_error_exception = data_bus_error_seen == `TRUE;
 `endif
 `ifdef CFG_MC_DIVIDE_ENABLED
 assign divide_by_zero_exception = divide_by_zero_x == `TRUE;
 `endif
 assign system_call_exception = (   (scall_x == `TRUE)
 `ifdef CFG_BUS_ERRORS_ENABLED
                                 && (valid_x == `TRUE)
 `endif
 			       );
 `ifdef CFG_DEBUG_ENABLED
 assign debug_exception_x =  (breakpoint_exception == `TRUE)
                          || (watchpoint_exception == `TRUE)
                          ;
 assign non_debug_exception_x = (system_call_exception == `TRUE)
 `ifdef CFG_JTAG_ENABLED
                             || (reset_exception == `TRUE)
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
                             || (instruction_bus_error_exception == `TRUE)
                             || (data_bus_error_exception == `TRUE)
 `endif
 `ifdef CFG_MC_DIVIDE_ENABLED
                             || (divide_by_zero_exception == `TRUE)
 `endif
 `ifdef CFG_INTERRUPTS_ENABLED
                             || (   (interrupt_exception == `TRUE)
 `ifdef LM32_SINGLE_STEP_ENABLED
                                 && (dc_ss == `FALSE)
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
  				&& (store_q_m == `FALSE)
 				&& (D_CYC_O == `FALSE)
 `endif
                                )
 `endif
                             ;
 assign exception_x = (debug_exception_x == `TRUE) || (non_debug_exception_x == `TRUE);
 `else
 assign exception_x =           (system_call_exception == `TRUE)
 `ifdef CFG_BUS_ERRORS_ENABLED
                             || (instruction_bus_error_exception == `TRUE)
                             || (data_bus_error_exception == `TRUE)
 `endif
 `ifdef CFG_MC_DIVIDE_ENABLED
                             || (divide_by_zero_exception == `TRUE)
 `endif
 `ifdef CFG_INTERRUPTS_ENABLED
                             || (   (interrupt_exception == `TRUE)
 `ifdef LM32_SINGLE_STEP_ENABLED
                                 && (dc_ss == `FALSE)
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
  				&& (store_q_m == `FALSE)
 				&& (D_CYC_O == `FALSE)
 `endif
                                )
 `endif
                             ;
 `endif
 // Exception ID
 always @(*)
 begin
 `ifdef CFG_DEBUG_ENABLED
 `ifdef CFG_JTAG_ENABLED
     if (reset_exception == `TRUE)
         eid_x = `LM32_EID_RESET;
     else
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
          if (data_bus_error_exception == `TRUE)
         eid_x = `LM32_EID_DATA_BUS_ERROR;
     else
 `endif
          if (breakpoint_exception == `TRUE)
         eid_x = `LM32_EID_BREAKPOINT;
     else
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
          if (data_bus_error_exception == `TRUE)
         eid_x = `LM32_EID_DATA_BUS_ERROR;
     else
          if (instruction_bus_error_exception == `TRUE)
         eid_x = `LM32_EID_INST_BUS_ERROR;
     else
 `endif
 `ifdef CFG_DEBUG_ENABLED
          if (watchpoint_exception == `TRUE)
         eid_x = `LM32_EID_WATCHPOINT;
     else
 `endif
 `ifdef CFG_MC_DIVIDE_ENABLED
          if (divide_by_zero_exception == `TRUE)
         eid_x = `LM32_EID_DIVIDE_BY_ZERO;
     else
 `endif
 `ifdef CFG_INTERRUPTS_ENABLED
          if (   (interrupt_exception == `TRUE)
 `ifdef LM32_SINGLE_STEP_ENABLED
              && (dc_ss == `FALSE)
 `endif
             )
         eid_x = `LM32_EID_INTERRUPT;
     else
 `endif
         eid_x = `LM32_EID_SCALL;
 end
 // Stall generation
 assign stall_a = (stall_f == `TRUE);
 assign stall_f = (stall_d == `TRUE);
 assign stall_d =   (stall_x == `TRUE)
                 || (   (interlock == `TRUE)
                     && (kill_d == `FALSE)
                    )
 		|| (   (   (eret_d == `TRUE)
 			|| (scall_d == `TRUE)
 			|| (bus_error_d == `TRUE)
 		       )
 		    && (   (load_q_x == `TRUE)
 			|| (load_q_m == `TRUE)
 			|| (store_q_x == `TRUE)
 			|| (store_q_m == `TRUE)
 			|| (D_CYC_O == `TRUE)
 		       )
                     && (kill_d == `FALSE)
 		   )
 `ifdef CFG_DEBUG_ENABLED
 		|| (   (   (break_d == `TRUE)
 			|| (bret_d == `TRUE)
 		       )
 		    && (   (load_q_x == `TRUE)
 			|| (store_q_x == `TRUE)
 			|| (load_q_m == `TRUE)
 			|| (store_q_m == `TRUE)
 			|| (D_CYC_O == `TRUE)
 		       )
                     && (kill_d == `FALSE)
 		   )
 `endif
                 || (   (csr_write_enable_d == `TRUE)
                     && (load_q_x == `TRUE)
                    )
                 ;
 assign stall_x =    (stall_m == `TRUE)
 `ifdef LM32_MC_ARITHMETIC_ENABLED
                  || (   (mc_stall_request_x == `TRUE)
                      && (kill_x == `FALSE)
                     )
 `endif
 `ifdef CFG_IROM_ENABLED
                  // Stall load/store instruction in D stage if there is an ongoing store
                  // operation to instruction ROM in M stage
                  || (   (irom_stall_request_x == `TRUE)
 		     && (   (load_d == `TRUE)
 			 || (store_d == `TRUE)
 			)
 		    )
 `endif
                  ;
 assign stall_m =    (stall_wb_load == `TRUE)
 `ifdef CFG_SIZE_OVER_SPEED
                  || (D_CYC_O == `TRUE)
 `else
                  || (   (D_CYC_O == `TRUE)
                      && (   (store_m == `TRUE)
 		         /*
 			  Bug: Following loop does not allow interrupts to be services since
 			  either D_CYC_O or store_m is always high during entire duration of
 			  loop.
 		          L1:	addi	r1, r1, 1
 			  	sw	(r2,0), r1
 			  	bi	L1
 			  Introduce a single-cycle stall when a wishbone cycle is in progress
 			  and a new store instruction is in Execute stage and a interrupt
 			  exception has occured. This stall will ensure that D_CYC_O and
 			  store_m will both be low for one cycle.
 			  */
 		         || ((store_x == `TRUE) && (interrupt_exception == `TRUE))
                          || (load_m == `TRUE)
                          || (load_x == `TRUE)
                         )
                     )
 `endif
 `ifdef CFG_DCACHE_ENABLED
                  || (dcache_stall_request == `TRUE)     // Need to stall in case a taken branch is in M stage and data cache is only being flush, so wont be restarted
 `endif
 `ifdef CFG_ICACHE_ENABLED
                  || (icache_stall_request == `TRUE)     // Pipeline needs to be stalled otherwise branches may be lost
                  || ((I_CYC_O == `TRUE) && ((branch_m == `TRUE) || (exception_m == `TRUE)))
 `else
 `ifdef CFG_IWB_ENABLED
                  || (I_CYC_O == `TRUE)
 `endif
 `endif
 `ifdef CFG_USER_ENABLED
                  || (   (user_valid == `TRUE)           // Stall whole pipeline, rather than just X stage, where the instruction is, so we don't have to worry about exceptions (maybe)
                      && (user_complete == `FALSE)
                     )
 `endif
                  ;
 // Qualify state changing control signals
 `ifdef LM32_MC_ARITHMETIC_ENABLED
 assign q_d = (valid_d == `TRUE) && (kill_d == `FALSE);
 `endif
 `ifdef CFG_MC_BARREL_SHIFT_ENABLED
 assign shift_left_q_d = (shift_left_d == `TRUE) && (q_d == `TRUE);
 assign shift_right_q_d = (shift_right_d == `TRUE) && (q_d == `TRUE);
 `endif
 `ifdef CFG_MC_MULTIPLY_ENABLED
 assign multiply_q_d = (multiply_d == `TRUE) && (q_d == `TRUE);
 `endif
 `ifdef CFG_MC_DIVIDE_ENABLED
 assign divide_q_d = (divide_d == `TRUE) && (q_d == `TRUE);
 assign modulus_q_d = (modulus_d == `TRUE) && (q_d == `TRUE);
 `endif
 assign q_x = (valid_x == `TRUE) && (kill_x == `FALSE);
 assign csr_write_enable_q_x = (csr_write_enable_x == `TRUE) && (q_x == `TRUE);
 assign eret_q_x = (eret_x == `TRUE) && (q_x == `TRUE);
 `ifdef CFG_DEBUG_ENABLED
 assign bret_q_x = (bret_x == `TRUE) && (q_x == `TRUE);
 `endif
 assign load_q_x = (load_x == `TRUE)
                && (q_x == `TRUE)
 `ifdef CFG_DEBUG_ENABLED
                && (bp_match == `FALSE)
 `endif
                   ;
 assign store_q_x = (store_x == `TRUE)
                && (q_x == `TRUE)
 `ifdef CFG_DEBUG_ENABLED
                && (bp_match == `FALSE)
 `endif
                   ;
 `ifdef CFG_USER_ENABLED
 assign user_valid = (x_result_sel_user_x == `TRUE) && (q_x == `TRUE);
 `endif
 assign q_m = (valid_m == `TRUE) && (kill_m == `FALSE) && (exception_m == `FALSE);
 assign load_q_m = (load_m == `TRUE) && (q_m == `TRUE);
 assign store_q_m = (store_m == `TRUE) && (q_m == `TRUE);
 `ifdef CFG_DEBUG_ENABLED
 assign debug_exception_q_w = ((debug_exception_w == `TRUE) && (valid_w == `TRUE));
 assign non_debug_exception_q_w = ((non_debug_exception_w == `TRUE) && (valid_w == `TRUE));
 `else
 assign exception_q_w = ((exception_w == `TRUE) && (valid_w == `TRUE));
 `endif
 // Don't qualify register write enables with kill, as the signal is needed early, and it doesn't matter if the instruction is killed (except for the actual write - but that is handled separately)
 assign write_enable_q_x = (write_enable_x == `TRUE) && (valid_x == `TRUE) && (branch_flushX_m == `FALSE);
 assign write_enable_q_m = (write_enable_m == `TRUE) && (valid_m == `TRUE);
 assign write_enable_q_w = (write_enable_w == `TRUE) && (valid_w == `TRUE);
 // The enable that actually does write the registers needs to be qualified with kill
 assign reg_write_enable_q_w = (write_enable_w == `TRUE) && (kill_w == `FALSE) && (valid_w == `TRUE);
 // Configuration (CFG) CSR
 assign cfg = {
               `LM32_REVISION,
               watchpoints[3:0],
               breakpoints[3:0],
               interrupts[5:0],
 `ifdef CFG_JTAG_UART_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef CFG_ROM_DEBUG_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef CFG_HW_DEBUG_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef CFG_DEBUG_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef CFG_ICACHE_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef CFG_DCACHE_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef CFG_CYCLE_COUNTER_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef CFG_USER_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef CFG_SIGN_EXTEND_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef LM32_BARREL_SHIFT_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef CFG_MC_DIVIDE_ENABLED
               `TRUE,
 `else
               `FALSE,
 `endif
 `ifdef LM32_MULTIPLY_ENABLED
               `TRUE
 `else
               `FALSE
 `endif
               };
 assign cfg2 = {
 'b0,
 `ifdef CFG_IROM_ENABLED
 		     `TRUE,
 `else
 		     `FALSE,
 `endif
 `ifdef CFG_DRAM_ENABLED
 		     `TRUE
 `else
 		     `FALSE
 `endif
 		     };
 // Cache flush
 `ifdef CFG_ICACHE_ENABLED
 assign iflush =    (csr_write_enable_d == `TRUE)
                 && (csr_d == `LM32_CSR_ICC)
                 && (stall_d == `FALSE)
                 && (kill_d == `FALSE)
                 && (valid_d == `TRUE);
 `endif
 `ifdef CFG_DCACHE_ENABLED
 assign dflush_x =  (csr_write_enable_q_x == `TRUE)
                 && (csr_x == `LM32_CSR_DCC);
 `endif
 // Extract CSR index
 assign csr_d = read_idx_0_d[`LM32_CSR_RNG];
 // CSR reads
 always @(*)
 begin
     case (csr_x)
 `ifdef CFG_INTERRUPTS_ENABLED
     `LM32_CSR_IE,
     `LM32_CSR_IM,
     `LM32_CSR_IP:   csr_read_data_x = interrupt_csr_read_data_x;
 `endif
 `ifdef CFG_CYCLE_COUNTER_ENABLED
     `LM32_CSR_CC:   csr_read_data_x = cc;
 `endif
     `LM32_CSR_CFG:  csr_read_data_x = cfg;
     `LM32_CSR_EBA:  csr_read_data_x = {eba, 8'h00};
 `ifdef CFG_DEBUG_ENABLED
     `LM32_CSR_DEBA: csr_read_data_x = {deba, 8'h00};
 `endif
 `ifdef CFG_JTAG_UART_ENABLED
     `LM32_CSR_JTX:  csr_read_data_x = jtx_csr_read_data;
     `LM32_CSR_JRX:  csr_read_data_x = jrx_csr_read_data;
 `endif
     `LM32_CSR_CFG2: csr_read_data_x = cfg2;
     default:        csr_read_data_x = {`LM32_WORD_WIDTH{1'bx}};
     endcase
 end
 /////////////////////////////////////////////////////
 // Sequential Logic
 /////////////////////////////////////////////////////
 // Exception Base Address (EBA) CSR
 always @(posedge clk_i `CFG_RESET_SENSITIVITY)
 begin
     if (rst_i == `TRUE)
         eba <= #1 eba_reset[`LM32_PC_WIDTH+2-1:8];
     else
     begin
         if ((csr_write_enable_q_x == `TRUE) && (csr_x == `LM32_CSR_EBA) && (stall_x == `FALSE))
             eba <= #1 operand_1_x[`LM32_PC_WIDTH+2-1:8];
 `ifdef CFG_HW_DEBUG_ENABLED
         if ((jtag_csr_write_enable == `TRUE) && (jtag_csr == `LM32_CSR_EBA))
             eba <= #1 jtag_csr_write_data[`LM32_PC_WIDTH+2-1:8];
 `endif
     end
 end
 `ifdef CFG_DEBUG_ENABLED
 // Debug Exception Base Address (DEBA) CSR
 always @(posedge clk_i `CFG_RESET_SENSITIVITY)
 begin
     if (rst_i == `TRUE)
         deba <= #1 deba_reset[`LM32_PC_WIDTH+2-1:8];
     else
     begin
         if ((csr_write_enable_q_x == `TRUE) && (csr_x == `LM32_CSR_DEBA) && (stall_x == `FALSE))
             deba <= #1 operand_1_x[`LM32_PC_WIDTH+2-1:8];
 `ifdef CFG_HW_DEBUG_ENABLED
         if ((jtag_csr_write_enable == `TRUE) && (jtag_csr == `LM32_CSR_DEBA))
             deba <= #1 jtag_csr_write_data[`LM32_PC_WIDTH+2-1:8];
 `endif
     end
 end
 `endif
 // Cycle Counter (CC) CSR
 `ifdef CFG_CYCLE_COUNTER_ENABLED
 always @(posedge clk_i `CFG_RESET_SENSITIVITY)
 begin
     if (rst_i == `TRUE)
         cc <= #1 {`LM32_WORD_WIDTH{1'b0}};
     else
         cc <= #1 cc + 1'b1;
 end
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
 // Watch for data bus errors
 always @(posedge clk_i `CFG_RESET_SENSITIVITY)
 begin
     if (rst_i == `TRUE)
         data_bus_error_seen <= #1 `FALSE;
     else
     begin
         // Set flag when bus error is detected
         if ((D_ERR_I == `TRUE) && (D_CYC_O == `TRUE))
             data_bus_error_seen <= #1 `TRUE;
         // Clear flag when exception is taken
         if ((exception_m == `TRUE) && (kill_m == `FALSE))
             data_bus_error_seen <= #1 `FALSE;
     end
 end
 `endif
 // Valid bits to indicate whether an instruction in a partcular pipeline stage is valid or not
 `ifdef CFG_ICACHE_ENABLED
 `ifdef CFG_DCACHE_ENABLED
 always @(*)
 begin
     if (   (icache_refill_request == `TRUE)
         || (dcache_refill_request == `TRUE)
        )
         valid_a = `FALSE;
     else if (   (icache_restart_request == `TRUE)
              || (dcache_restart_request == `TRUE)
             )
         valid_a = `TRUE;
     else
         valid_a = !icache_refilling && !dcache_refilling;
 end
 `else
 always @(*)
 begin
     if (icache_refill_request == `TRUE)
         valid_a = `FALSE;
     else if (icache_restart_request == `TRUE)
         valid_a = `TRUE;
     else
         valid_a = !icache_refilling;
 end
 `endif
 `else
 `ifdef CFG_DCACHE_ENABLED
 always @(*)
 begin
     if (dcache_refill_request == `TRUE)
         valid_a = `FALSE;
     else if (dcache_restart_request == `TRUE)
         valid_a = `TRUE;
     else
         valid_a = !dcache_refilling;
 end
 `endif
 `endif
 always @(posedge clk_i `CFG_RESET_SENSITIVITY)
 begin
     if (rst_i == `TRUE)
     begin
         valid_f <= #1 `FALSE;
         valid_d <= #1 `FALSE;
         valid_x <= #1 `FALSE;
         valid_m <= #1 `FALSE;
         valid_w <= #1 `FALSE;
     end
     else
     begin
         if ((kill_f == `TRUE) || (stall_a == `FALSE))
 `ifdef LM32_CACHE_ENABLED
             valid_f <= #1 valid_a;
 `else
             valid_f <= #1 `TRUE;
 `endif
         else if (stall_f == `FALSE)
             valid_f <= #1 `FALSE;
         if (kill_d == `TRUE)
             valid_d <= #1 `FALSE;
         else if (stall_f == `FALSE)
             valid_d <= #1 valid_f & !kill_f;
         else if (stall_d == `FALSE)
             valid_d <= #1 `FALSE;
         if (stall_d == `FALSE)
             valid_x <= #1 valid_d & !kill_d;
         else if (kill_x == `TRUE)
             valid_x <= #1 `FALSE;
         else if (stall_x == `FALSE)
             valid_x <= #1 `FALSE;
         if (kill_m == `TRUE)
             valid_m <= #1 `FALSE;
         else if (stall_x == `FALSE)
             valid_m <= #1 valid_x & !kill_x;
         else if (stall_m == `FALSE)
             valid_m <= #1 `FALSE;
         if (stall_m == `FALSE)
             valid_w <= #1 valid_m & !kill_m;
         else
             valid_w <= #1 `FALSE;
     end
 end
 // Microcode pipeline registers
 always @(posedge clk_i `CFG_RESET_SENSITIVITY)
 begin
     if (rst_i == `TRUE)
     begin
 `ifdef CFG_USER_ENABLED
         user_opcode <= #1 {`LM32_USER_OPCODE_WIDTH{1'b0}};
 `endif
         operand_0_x <= #1 {`LM32_WORD_WIDTH{1'b0}};
         operand_1_x <= #1 {`LM32_WORD_WIDTH{1'b0}};
         store_operand_x <= #1 {`LM32_WORD_WIDTH{1'b0}};
         branch_target_x <= #1 {`LM32_WORD_WIDTH{1'b0}};
         x_result_sel_csr_x <= #1 `FALSE;
 `ifdef LM32_MC_ARITHMETIC_ENABLED
         x_result_sel_mc_arith_x <= #1 `FALSE;
 `endif
 `ifdef LM32_NO_BARREL_SHIFT
         x_result_sel_shift_x <= #1 `FALSE;
 `endif
 `ifdef CFG_SIGN_EXTEND_ENABLED
         x_result_sel_sext_x <= #1 `FALSE;
 `endif
 	x_result_sel_logic_x <= #1 `FALSE;
 `ifdef CFG_USER_ENABLED
         x_result_sel_user_x <= #1 `FALSE;
 `endif
         x_result_sel_add_x <= #1 `FALSE;
         m_result_sel_compare_x <= #1 `FALSE;
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
         m_result_sel_shift_x <= #1 `FALSE;
 `endif
         w_result_sel_load_x <= #1 `FALSE;
 `ifdef CFG_PL_MULTIPLY_ENABLED
         w_result_sel_mul_x <= #1 `FALSE;
 `endif
         x_bypass_enable_x <= #1 `FALSE;
         m_bypass_enable_x <= #1 `FALSE;
         write_enable_x <= #1 `FALSE;
         write_idx_x <= #1 {`LM32_REG_IDX_WIDTH{1'b0}};
         csr_x <= #1 {`LM32_CSR_WIDTH{1'b0}};
         load_x <= #1 `FALSE;
         store_x <= #1 `FALSE;
         size_x <= #1 {`LM32_SIZE_WIDTH{1'b0}};
         sign_extend_x <= #1 `FALSE;
         adder_op_x <= #1 `FALSE;
         adder_op_x_n <= #1 `FALSE;
         logic_op_x <= #1 4'h0;
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
         direction_x <= #1 `FALSE;
 `endif
 `ifdef CFG_ROTATE_ENABLED
         rotate_x <= #1 `FALSE;
 `endif
         branch_x <= #1 `FALSE;
         branch_predict_x <= #1 `FALSE;
         branch_predict_taken_x <= #1 `FALSE;
         condition_x <= #1 `LM32_CONDITION_U1;
 `ifdef CFG_DEBUG_ENABLED
         break_x <= #1 `FALSE;
 `endif
         scall_x <= #1 `FALSE;
         eret_x <= #1 `FALSE;
 `ifdef CFG_DEBUG_ENABLED
         bret_x <= #1 `FALSE;
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
         bus_error_x <= #1 `FALSE;
         data_bus_error_exception_m <= #1 `FALSE;
 `endif
         csr_write_enable_x <= #1 `FALSE;
         operand_m <= #1 {`LM32_WORD_WIDTH{1'b0}};
         branch_target_m <= #1 {`LM32_WORD_WIDTH{1'b0}};
         m_result_sel_compare_m <= #1 `FALSE;
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
         m_result_sel_shift_m <= #1 `FALSE;
 `endif
         w_result_sel_load_m <= #1 `FALSE;
 `ifdef CFG_PL_MULTIPLY_ENABLED
         w_result_sel_mul_m <= #1 `FALSE;
 `endif
         m_bypass_enable_m <= #1 `FALSE;
         branch_m <= #1 `FALSE;
         branch_predict_m <= #1 `FALSE;
 	branch_predict_taken_m <= #1 `FALSE;
         exception_m <= #1 `FALSE;
         load_m <= #1 `FALSE;
         store_m <= #1 `FALSE;
         write_enable_m <= #1 `FALSE;
         write_idx_m <= #1 {`LM32_REG_IDX_WIDTH{1'b0}};
         condition_met_m <= #1 `FALSE;
 `ifdef CFG_DCACHE_ENABLED
         dflush_m <= #1 `FALSE;
 `endif
 `ifdef CFG_DEBUG_ENABLED
         debug_exception_m <= #1 `FALSE;
         non_debug_exception_m <= #1 `FALSE;
 `endif
         operand_w <= #1 {`LM32_WORD_WIDTH{1'b0}};
         w_result_sel_load_w <= #1 `FALSE;
 `ifdef CFG_PL_MULTIPLY_ENABLED
         w_result_sel_mul_w <= #1 `FALSE;
 `endif
         write_idx_w <= #1 {`LM32_REG_IDX_WIDTH{1'b0}};
         write_enable_w <= #1 `FALSE;
 `ifdef CFG_DEBUG_ENABLED
         debug_exception_w <= #1 `FALSE;
         non_debug_exception_w <= #1 `FALSE;
 `else
         exception_w <= #1 `FALSE;
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
         memop_pc_w <= #1 {`LM32_PC_WIDTH{1'b0}};
 `endif
     end
     else
     begin
         // D/X stage registers
         if (stall_x == `FALSE)
         begin
 `ifdef CFG_USER_ENABLED
             user_opcode <= #1 user_opcode_d;
 `endif
             operand_0_x <= #1 d_result_0;
             operand_1_x <= #1 d_result_1;
             store_operand_x <= #1 bypass_data_1;
             branch_target_x <= #1 branch_reg_d == `TRUE ? bypass_data_0[`LM32_PC_RNG] : branch_target_d;
             x_result_sel_csr_x <= #1 x_result_sel_csr_d;
 `ifdef LM32_MC_ARITHMETIC_ENABLED
             x_result_sel_mc_arith_x <= #1 x_result_sel_mc_arith_d;
 `endif
 `ifdef LM32_NO_BARREL_SHIFT
             x_result_sel_shift_x <= #1 x_result_sel_shift_d;
 `endif
 `ifdef CFG_SIGN_EXTEND_ENABLED
             x_result_sel_sext_x <= #1 x_result_sel_sext_d;
 `endif
 	    x_result_sel_logic_x <= #1 x_result_sel_logic_d;
 `ifdef CFG_USER_ENABLED
             x_result_sel_user_x <= #1 x_result_sel_user_d;
 `endif
             x_result_sel_add_x <= #1 x_result_sel_add_d;
             m_result_sel_compare_x <= #1 m_result_sel_compare_d;
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
             m_result_sel_shift_x <= #1 m_result_sel_shift_d;
 `endif
             w_result_sel_load_x <= #1 w_result_sel_load_d;
 `ifdef CFG_PL_MULTIPLY_ENABLED
             w_result_sel_mul_x <= #1 w_result_sel_mul_d;
 `endif
             x_bypass_enable_x <= #1 x_bypass_enable_d;
             m_bypass_enable_x <= #1 m_bypass_enable_d;
             load_x <= #1 load_d;
             store_x <= #1 store_d;
             branch_x <= #1 branch_d;
 	    branch_predict_x <= #1 branch_predict_d;
 	    branch_predict_taken_x <= #1 branch_predict_taken_d;
 	    write_idx_x <= #1 write_idx_d;
             csr_x <= #1 csr_d;
             size_x <= #1 size_d;
             sign_extend_x <= #1 sign_extend_d;
             adder_op_x <= #1 adder_op_d;
             adder_op_x_n <= #1 ~adder_op_d;
             logic_op_x <= #1 logic_op_d;
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
             direction_x <= #1 direction_d;
 `endif
 `ifdef CFG_ROTATE_ENABLED
             rotate_x <= #1 rotate_d;
 `endif
             condition_x <= #1 condition_d;
             csr_write_enable_x <= #1 csr_write_enable_d;
 `ifdef CFG_DEBUG_ENABLED
             break_x <= #1 break_d;
 `endif
             scall_x <= #1 scall_d;
 `ifdef CFG_BUS_ERRORS_ENABLED
             bus_error_x <= #1 bus_error_d;
 `endif
             eret_x <= #1 eret_d;
 `ifdef CFG_DEBUG_ENABLED
             bret_x <= #1 bret_d;
 `endif
             write_enable_x <= #1 write_enable_d;
         end
         // X/M stage registers
         if (stall_m == `FALSE)
         begin
             operand_m <= #1 x_result;
             m_result_sel_compare_m <= #1 m_result_sel_compare_x;
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
             m_result_sel_shift_m <= #1 m_result_sel_shift_x;
 `endif
             if (exception_x == `TRUE)
             begin
                 w_result_sel_load_m <= #1 `FALSE;
 `ifdef CFG_PL_MULTIPLY_ENABLED
                 w_result_sel_mul_m <= #1 `FALSE;
 `endif
             end
             else
             begin
                 w_result_sel_load_m <= #1 w_result_sel_load_x;
 `ifdef CFG_PL_MULTIPLY_ENABLED
                 w_result_sel_mul_m <= #1 w_result_sel_mul_x;
 `endif
             end
             m_bypass_enable_m <= #1 m_bypass_enable_x;
 `ifdef CFG_PL_BARREL_SHIFT_ENABLED
 `endif
             load_m <= #1 load_x;
             store_m <= #1 store_x;
 `ifdef CFG_FAST_UNCONDITIONAL_BRANCH
             branch_m <= #1 branch_x && !branch_taken_x;
 `else
             branch_m <= #1 branch_x;
 	    branch_predict_m <= #1 branch_predict_x;
 	    branch_predict_taken_m <= #1 branch_predict_taken_x;
 `endif
 `ifdef CFG_DEBUG_ENABLED
 	   // Data bus errors are generated by the wishbone and are
 	   // made known to the processor only in next cycle (as a
 	   // non-debug exception). A break instruction can be seen
 	   // in same cycle (causing a debug exception). Handle non
 	   // -debug exception first!
             if (non_debug_exception_x == `TRUE)
                 write_idx_m <= #1 `LM32_EA_REG;
             else if (debug_exception_x == `TRUE)
                 write_idx_m <= #1 `LM32_BA_REG;
             else
                 write_idx_m <= #1 write_idx_x;
 `else
             if (exception_x == `TRUE)
                 write_idx_m <= #1 `LM32_EA_REG;
             else
                 write_idx_m <= #1 write_idx_x;
 `endif
             condition_met_m <= #1 condition_met_x;
 `ifdef CFG_DEBUG_ENABLED
 	   if (exception_x == `TRUE)
 	     if ((dc_re == `TRUE)
  `ifdef CFG_ALTERNATE_EBA
 		 || (at_debug == `TRUE)
  `endif
 		 || ((debug_exception_x == `TRUE)
 		     && (non_debug_exception_x == `FALSE)))
 	       branch_target_m <= #1 {deba, eid_x, {3{1'b0}}};
 	     else
 	       branch_target_m <= #1 {eba, eid_x, {3{1'b0}}};
 	   else
 	     branch_target_m <= #1 branch_target_x;
 `else
             branch_target_m <= #1 exception_x == `TRUE ? {eba, eid_x, {3{1'b0}}} : branch_target_x;
 `endif
 `ifdef CFG_TRACE_ENABLED
             eid_m <= #1 eid_x;
 `endif
 `ifdef CFG_DCACHE_ENABLED
             dflush_m <= #1 dflush_x;
 `endif
             eret_m <= #1 eret_q_x;
 `ifdef CFG_DEBUG_ENABLED
             bret_m <= #1 bret_q_x;
 `endif
             write_enable_m <= #1 exception_x == `TRUE ? `TRUE : write_enable_x;
 `ifdef CFG_DEBUG_ENABLED
             debug_exception_m <= #1 debug_exception_x;
             non_debug_exception_m <= #1 non_debug_exception_x;
 `endif
         end
         // State changing regs
         if (stall_m == `FALSE)
         begin
             if ((exception_x == `TRUE) && (q_x == `TRUE) && (stall_x == `FALSE))
                 exception_m <= #1 `TRUE;
             else
                 exception_m <= #1 `FALSE;
 `ifdef CFG_BUS_ERRORS_ENABLED
 	   data_bus_error_exception_m <= #1    (data_bus_error_exception == `TRUE)
 `ifdef CFG_DEBUG_ENABLED
 					 && (reset_exception == `FALSE)
 `endif
 					 ;
 `endif
 	end
         // M/W stage registers
 `ifdef CFG_BUS_ERRORS_ENABLED
         operand_w <= #1 exception_m == `TRUE ? (data_bus_error_exception_m ? {memop_pc_w, 2'b00} : {pc_m, 2'b00}) : m_result;
 `else
         operand_w <= #1 exception_m == `TRUE ? {pc_m, 2'b00} : m_result;
 `endif
         w_result_sel_load_w <= #1 w_result_sel_load_m;
 `ifdef CFG_PL_MULTIPLY_ENABLED
         w_result_sel_mul_w <= #1 w_result_sel_mul_m;
 `endif
         write_idx_w <= #1 write_idx_m;
 `ifdef CFG_TRACE_ENABLED
         eid_w <= #1 eid_m;
         eret_w <= #1 eret_m;
 `ifdef CFG_DEBUG_ENABLED
         bret_w <= #1 bret_m;
 `endif
 `endif
         write_enable_w <= #1 write_enable_m;
 `ifdef CFG_DEBUG_ENABLED
         debug_exception_w <= #1 debug_exception_m;
         non_debug_exception_w <= #1 non_debug_exception_m;
 `else
         exception_w <= #1 exception_m;
 `endif
 `ifdef CFG_BUS_ERRORS_ENABLED
         if (   (stall_m == `FALSE)
 	    && (data_bus_error_exception == `FALSE)
             && (   (load_q_m == `TRUE)
                 || (store_q_m == `TRUE)
                )
 	   )
           memop_pc_w <= #1 pc_m;
 `endif
     end
 end
 `ifdef CFG_EBR_POSEDGE_REGISTER_FILE
 // Buffer data read from register file, in case a stall occurs, and watch for
 // any writes to the modified registers
 always @(posedge clk_i `CFG_RESET_SENSITIVITY)
 begin
     if (rst_i == `TRUE)
     begin
         use_buf <= #1 `FALSE;
         reg_data_buf_0 <= #1 {`LM32_WORD_WIDTH{1'b0}};
         reg_data_buf_1 <= #1 {`LM32_WORD_WIDTH{1'b0}};
     end
     else
     begin
         if (stall_d == `FALSE)
             use_buf <= #1 `FALSE;
         else if (use_buf == `FALSE)
         begin
             reg_data_buf_0 <= #1 reg_data_live_0;
             reg_data_buf_1 <= #1 reg_data_live_1;
             use_buf <= #1 `TRUE;
         end
         if (reg_write_enable_q_w == `TRUE)
         begin
             if (write_idx_w == read_idx_0_d)
                 reg_data_buf_0 <= #1 w_result;
             if (write_idx_w == read_idx_1_d)
                 reg_data_buf_1 <= #1 w_result;
         end
     end
 end
 `endif
 `ifdef LM32_EBR_REGISTER_FILE
 `else
 // Register file write port
 always @(posedge clk_i `CFG_RESET_SENSITIVITY)
 begin
     if (rst_i == `TRUE) begin
         registers[0] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[1] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[2] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[3] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[4] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[5] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[6] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[7] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[8] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[9] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[10] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[11] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[12] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[13] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[14] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[15] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[16] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[17] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[18] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[19] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[20] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[21] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[22] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[23] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[24] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[25] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[26] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[27] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[28] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[29] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[30] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         registers[31] <= #1 {`LM32_WORD_WIDTH{1'b0}};
         end
     else begin
         if (reg_write_enable_q_w == `TRUE)
           registers[write_idx_w] <= #1 w_result;
         end
 end
 `endif
 `ifdef CFG_TRACE_ENABLED
 // PC tracing logic
 always @(posedge clk_i `CFG_RESET_SENSITIVITY)
 begin
     if (rst_i == `TRUE)
     begin
         trace_pc_valid <= #1 `FALSE;
         trace_pc <= #1 {`LM32_PC_WIDTH{1'b0}};
         trace_exception <= #1 `FALSE;
         trace_eid <= #1 `LM32_EID_RESET;
         trace_eret <= #1 `FALSE;
 `ifdef CFG_DEBUG_ENABLED
         trace_bret <= #1 `FALSE;
 `endif
         pc_c <= #1 `CFG_EBA_RESET/4;
     end
     else
     begin
         trace_pc_valid <= #1 `FALSE;
         // Has an exception occured
 `ifdef CFG_DEBUG_ENABLED
         if ((debug_exception_q_w == `TRUE) || (non_debug_exception_q_w == `TRUE))
 `else
         if (exception_q_w == `TRUE)
 `endif
         begin
             trace_exception <= #1 `TRUE;
             trace_pc_valid <= #1 `TRUE;
             trace_pc <= #1 pc_w;
             trace_eid <= #1 eid_w;
         end
         else
             trace_exception <= #1 `FALSE;
         if ((valid_w == `TRUE) && (!kill_w))
         begin
             // An instruction is commiting. Determine if it is non-sequential
             if (pc_c + 1'b1 != pc_w)
             begin
                 // Non-sequential instruction
                 trace_pc_valid <= #1 `TRUE;
                 trace_pc <= #1 pc_w;
             end
             // Record PC so we can determine if next instruction is sequential or not
             pc_c <= #1 pc_w;
             // Indicate if it was an eret/bret instruction
             trace_eret <= #1 eret_w;
 `ifdef CFG_DEBUG_ENABLED
             trace_bret <= #1 bret_w;
 `endif
         end
         else
         begin
             trace_eret <= #1 `FALSE;
 `ifdef CFG_DEBUG_ENABLED
             trace_bret <= #1 `FALSE;
 `endif
         end
     end
 end
 `endif
 /////////////////////////////////////////////////////
 // Behavioural Logic
 /////////////////////////////////////////////////////
 // synthesis translate_off
 // Reset register 0. Only needed for simulation.
 initial
 begin
 `ifdef LM32_EBR_REGISTER_FILE
     reg_0.mem[0] = {`LM32_WORD_WIDTH{1'b0}};
     reg_1.mem[0] = {`LM32_WORD_WIDTH{1'b0}};
 `else
     registers[0] = {`LM32_WORD_WIDTH{1'b0}};
 `endif
 end
 // synthesis translate_on
 endmodule

IPCores/lm32_cpu / annotate

lm32_cpu.v@73de224304c1 (annotated)

lm32_cpu.v