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-- #################################################################################################
-- # << NEORV32 - Main VHDL package file >>                                                        #
-- # ********************************************************************************************* #
-- # BSD 3-Clause License                                                                          #
-- #                                                                                               #
-- # Copyright (c) 2021, Stephan Nolting. All rights reserved.                                     #
-- #                                                                                               #
-- # Redistribution and use in source and binary forms, with or without modification, are          #
-- # permitted provided that the following conditions are met:                                     #
-- #                                                                                               #
-- # 1. Redistributions of source code must retain the above copyright notice, this list of        #
-- #    conditions and the following disclaimer.                                                   #
-- #                                                                                               #
-- # 2. Redistributions in binary form must reproduce the above copyright notice, this list of     #
-- #    conditions and the following disclaimer in the documentation and/or other materials        #
-- #    provided with the distribution.                                                            #
-- #                                                                                               #
-- # 3. Neither the name of the copyright holder nor the names of its contributors may be used to  #
-- #    endorse or promote products derived from this software without specific prior written      #
-- #    permission.                                                                                #
-- #                                                                                               #
-- # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS   #
-- # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF               #
-- # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE    #
-- # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,     #
-- # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE #
-- # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED    #
-- # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING     #
-- # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED  #
-- # OF THE POSSIBILITY OF SUCH DAMAGE.                                                            #
-- # ********************************************************************************************* #
-- # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #
-- #################################################################################################
 
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
 
package neorv32_package is
 
  -- Architecture Configuration -------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- address space --
  constant ispace_base_c : std_ulogic_vector(31 downto 0) := x"00000000"; -- default instruction memory address space base address
  constant dspace_base_c : std_ulogic_vector(31 downto 0) := x"80000000"; -- default data memory address space base address
 
  -- (external) bus interface --
  constant bus_timeout_c     : natural := 127; -- cycles after which an *unacknowledged* bus access will timeout and trigger a bus fault exception (min 2)
  constant wb_pipe_mode_c    : boolean := false; -- *external* bus protocol: false=classic/standard wishbone mode (default), true=pipelined wishbone mode
  constant xbus_big_endian_c : boolean := true; -- external memory access byte order: true=big endian (default); false=little endian
 
  -- CPU core --
  constant ipb_entries_c : natural := 2; -- entries in CPU instruction prefetch buffer, has to be a power of 2, default=2
 
  -- "critical" number of PMP regions --
  -- if more PMP regions (> pmp_num_regions_critical_c) are defined, another register stage is automatically
  -- inserted into the memory interfaces increasing instruction fetch & data access latency by +1 cycle!
  constant pmp_num_regions_critical_c : natural := 8;
 
  -- Architecture Constants (do not modify!) ------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  constant data_width_c   : natural := 32; -- native data path width - do not change!
  constant hw_version_c   : std_ulogic_vector(31 downto 0) := x"01050104"; -- no touchy!
  constant pmp_max_r_c    : natural := 8; -- max PMP regions - FIXED!
  constant archid_c       : natural := 19; -- official NEORV32 architecture ID - hands off!
  constant rf_r0_is_reg_c : boolean := true; -- reg_file.r0 is a *physical register* that has to be initialized to zero by the CPU HW
 
  -- Helper Functions -----------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  function index_size_f(input : natural) return natural;
  function cond_sel_natural_f(cond : boolean; val_t : natural; val_f : natural) return natural;
  function cond_sel_stdulogicvector_f(cond : boolean; val_t : std_ulogic_vector; val_f : std_ulogic_vector) return std_ulogic_vector;
  function bool_to_ulogic_f(cond : boolean) return std_ulogic;
  function or_all_f(a : std_ulogic_vector) return std_ulogic;
  function and_all_f(a : std_ulogic_vector) return std_ulogic;
  function xor_all_f(a : std_ulogic_vector) return std_ulogic;
  function xnor_all_f(a : std_ulogic_vector) return std_ulogic;
  function to_hexchar_f(input : std_ulogic_vector(3 downto 0)) return character;
  function hexchar_to_stdulogicvector_f(input : character) return std_ulogic_vector;
  function bit_rev_f(input : std_ulogic_vector) return std_ulogic_vector;
  function is_power_of_two_f(input : natural) return boolean;
  function bswap32_f(input : std_ulogic_vector) return std_ulogic_vector;
 
  -- Internal Types -------------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  type pmp_ctrl_if_t is array (0 to 63) of std_ulogic_vector(07 downto 0);
  type pmp_addr_if_t is array (0 to 63) of std_ulogic_vector(33 downto 0);
  type cp_data_if_t  is array (0 to 7)  of std_ulogic_vector(data_width_c-1 downto 0);
 
  -- Processor-Internal Address Space Layout ------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- Internal Instruction Memory (IMEM) and Date Memory (DMEM) --
  constant imem_base_c          : std_ulogic_vector(data_width_c-1 downto 0) := ispace_base_c; -- internal instruction memory base address
  constant dmem_base_c          : std_ulogic_vector(data_width_c-1 downto 0) := dspace_base_c; -- internal data memory base address
  --> internal data/instruction memory sizes are configured via top's generics
 
  -- Internal Bootloader ROM --
  constant boot_rom_base_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFF0000"; -- bootloader base address, fixed!
  constant boot_rom_size_c      : natural := 4*1024; -- module's address space in bytes
  constant boot_rom_max_size_c  : natural := 32*1024; -- max module's address space in bytes, fixed!
 
  -- IO: Peripheral Devices ("IO") Area --
  -- Control register(s) (including the device-enable) should be located at the base address of each device
  constant io_base_c            : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF00";
  constant io_size_c            : natural := 64*4; -- module's address space in bytes, fixed!
 
  -- Custom Functions Subsystem (CFS) --
  constant cfs_base_c           : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF00"; -- base address
  constant cfs_size_c           : natural := 32*4; -- module's address space in bytes
  constant cfs_reg0_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF00";
  constant cfs_reg1_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF04";
  constant cfs_reg2_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF08";
  constant cfs_reg3_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF0C";
  constant cfs_reg4_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF10";
  constant cfs_reg5_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF14";
  constant cfs_reg6_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF18";
  constant cfs_reg7_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF1C";
  constant cfs_reg8_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF20";
  constant cfs_reg9_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF24";
  constant cfs_reg10_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF28";
  constant cfs_reg11_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF2C";
  constant cfs_reg12_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF30";
  constant cfs_reg13_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF34";
  constant cfs_reg14_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF38";
  constant cfs_reg15_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF3C";
  constant cfs_reg16_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF40";
  constant cfs_reg17_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF44";
  constant cfs_reg18_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF48";
  constant cfs_reg19_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF4C";
  constant cfs_reg20_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF50";
  constant cfs_reg21_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF54";
  constant cfs_reg22_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF58";
  constant cfs_reg23_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF5C";
  constant cfs_reg24_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF60";
  constant cfs_reg25_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF64";
  constant cfs_reg26_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF68";
  constant cfs_reg27_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF6C";
  constant cfs_reg28_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF70";
  constant cfs_reg29_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF74";
  constant cfs_reg30_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF78";
  constant cfs_reg31_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF7C";
 
  -- General Purpose Input/Output Unit (GPIO) --
  constant gpio_base_c          : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF80"; -- base address
  constant gpio_size_c          : natural := 2*4; -- module's address space in bytes
  constant gpio_in_addr_c       : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF80";
  constant gpio_out_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF84";
 
  -- True Random Number Generator (TRNG) --
  constant trng_base_c          : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF88"; -- base address
  constant trng_size_c          : natural := 1*4; -- module's address space in bytes
  constant trng_ctrl_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF88";
 
  -- Watch Dog Timer (WDT) --
  constant wdt_base_c           : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF8C"; -- base address
  constant wdt_size_c           : natural := 1*4; -- module's address space in bytes
  constant wdt_ctrl_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF8C";
 
  -- Machine System Timer (MTIME) --
  constant mtime_base_c         : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF90"; -- base address
  constant mtime_size_c         : natural := 4*4; -- module's address space in bytes
  constant mtime_time_lo_addr_c : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF90";
  constant mtime_time_hi_addr_c : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF94";
  constant mtime_cmp_lo_addr_c  : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF98";
  constant mtime_cmp_hi_addr_c  : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFF9C";
 
  -- Universal Asynchronous Receiver/Transmitter (UART) --
  constant uart_base_c          : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFA0"; -- base address
  constant uart_size_c          : natural := 2*4; -- module's address space in bytes
  constant uart_ctrl_addr_c     : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFA0";
  constant uart_rtx_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFA4";
 
  -- Serial Peripheral Interface (SPI) --
  constant spi_base_c           : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFA8"; -- base address
  constant spi_size_c           : natural := 2*4; -- module's address space in bytes
  constant spi_ctrl_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFA8";
  constant spi_rtx_addr_c       : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFAC";
 
  -- Two Wire Interface (TWI) --
  constant twi_base_c           : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFB0"; -- base address
  constant twi_size_c           : natural := 2*4; -- module's address space in bytes
  constant twi_ctrl_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFB0";
  constant twi_rtx_addr_c       : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFB4";
 
  -- Pulse-Width Modulation Controller (PWM) --
  constant pwm_base_c           : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFB8"; -- base address
  constant pwm_size_c           : natural := 2*4; -- module's address space in bytes
  constant pwm_ctrl_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFB8";
  constant pwm_duty_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFBC";
 
  -- Numerically-Controlled Oscillator (NCO) --
  constant nco_base_c           : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFC0"; -- base address
  constant nco_size_c           : natural := 4*4; -- module's address space in bytes
  constant nco_ctrl_addr_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFC0";
  constant nco_ch0_addr_c       : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFC4";
  constant nco_ch1_addr_c       : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFC8";
  constant nco_ch2_addr_c       : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFCC";
 
  -- reserved --
--constant reserved_base_c      : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFD0"; -- base address
--constant reserved_size_c      : natural := 4*4; -- module's address space in bytes
 
  -- System Information Memory (SYSINFO) --
  constant sysinfo_base_c       : std_ulogic_vector(data_width_c-1 downto 0) := x"FFFFFFE0"; -- base address
  constant sysinfo_size_c       : natural := 8*4; -- module's address space in bytes
 
  -- Main Control Bus -----------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- register file --
  constant ctrl_rf_in_mux_c     : natural :=  0; -- input source select lsb (0=MEM, 1=ALU)
  constant ctrl_rf_rs1_adr0_c   : natural :=  1; -- source register 1 address bit 0
  constant ctrl_rf_rs1_adr1_c   : natural :=  2; -- source register 1 address bit 1
  constant ctrl_rf_rs1_adr2_c   : natural :=  3; -- source register 1 address bit 2
  constant ctrl_rf_rs1_adr3_c   : natural :=  4; -- source register 1 address bit 3
  constant ctrl_rf_rs1_adr4_c   : natural :=  5; -- source register 1 address bit 4
  constant ctrl_rf_rs2_adr0_c   : natural :=  6; -- source register 2 address bit 0
  constant ctrl_rf_rs2_adr1_c   : natural :=  7; -- source register 2 address bit 1
  constant ctrl_rf_rs2_adr2_c   : natural :=  8; -- source register 2 address bit 2
  constant ctrl_rf_rs2_adr3_c   : natural :=  9; -- source register 2 address bit 3
  constant ctrl_rf_rs2_adr4_c   : natural := 10; -- source register 2 address bit 4
  constant ctrl_rf_rd_adr0_c    : natural := 11; -- destiantion register address bit 0
  constant ctrl_rf_rd_adr1_c    : natural := 12; -- destiantion register address bit 1
  constant ctrl_rf_rd_adr2_c    : natural := 13; -- destiantion register address bit 2
  constant ctrl_rf_rd_adr3_c    : natural := 14; -- destiantion register address bit 3
  constant ctrl_rf_rd_adr4_c    : natural := 15; -- destiantion register address bit 4
  constant ctrl_rf_wb_en_c      : natural := 16; -- write back enable
  constant ctrl_rf_r0_we_c      : natural := 17; -- force write access and force rd=r0
  -- alu --
  constant ctrl_alu_arith_c     : natural := 18; -- ALU arithmetic command
  constant ctrl_alu_logic0_c    : natural := 19; -- ALU logic command bit 0
  constant ctrl_alu_logic1_c    : natural := 20; -- ALU logic command bit 1
  constant ctrl_alu_func0_c     : natural := 21; -- ALU function select command bit 0
  constant ctrl_alu_func1_c     : natural := 22; -- ALU function select command bit 1
  constant ctrl_alu_addsub_c    : natural := 23; -- 0=ADD, 1=SUB
  constant ctrl_alu_opa_mux_c   : natural := 24; -- operand A select (0=rs1, 1=PC)
  constant ctrl_alu_opb_mux_c   : natural := 25; -- operand B select (0=rs2, 1=IMM)
  constant ctrl_alu_unsigned_c  : natural := 26; -- is unsigned ALU operation
  constant ctrl_alu_shift_dir_c : natural := 27; -- shift direction (0=left, 1=right)
  constant ctrl_alu_shift_ar_c  : natural := 28; -- is arithmetic shift
  -- bus interface --
  constant ctrl_bus_size_lsb_c  : natural := 29; -- transfer size lsb (00=byte, 01=half-word)
  constant ctrl_bus_size_msb_c  : natural := 30; -- transfer size msb (10=word, 11=?)
  constant ctrl_bus_rd_c        : natural := 31; -- read data request
  constant ctrl_bus_wr_c        : natural := 32; -- write data request
  constant ctrl_bus_if_c        : natural := 33; -- instruction fetch request
  constant ctrl_bus_mo_we_c     : natural := 34; -- memory address and data output register write enable
  constant ctrl_bus_mi_we_c     : natural := 35; -- memory data input register write enable
  constant ctrl_bus_unsigned_c  : natural := 36; -- is unsigned load
  constant ctrl_bus_ierr_ack_c  : natural := 37; -- acknowledge instruction fetch bus exceptions
  constant ctrl_bus_derr_ack_c  : natural := 38; -- acknowledge data access bus exceptions
  constant ctrl_bus_fence_c     : natural := 39; -- executed fence operation
  constant ctrl_bus_fencei_c    : natural := 40; -- executed fencei operation
  constant ctrl_bus_lock_c      : natural := 41; -- locked/exclusive bus access
  -- co-processors --
  constant ctrl_cp_id_lsb_c     : natural := 42; -- cp select ID lsb
  constant ctrl_cp_id_hsb_c     : natural := 43; -- cp select ID hsb
  constant ctrl_cp_id_msb_c     : natural := 44; -- cp select ID msb
  -- current privilege level --
  constant ctrl_priv_lvl_lsb_c  : natural := 45; -- privilege level lsb
  constant ctrl_priv_lvl_msb_c  : natural := 46; -- privilege level msb
  -- instruction's control blocks (used by cpu co-processors) --
  constant ctrl_ir_funct3_0_c   : natural := 47; -- funct3 bit 0
  constant ctrl_ir_funct3_1_c   : natural := 48; -- funct3 bit 1
  constant ctrl_ir_funct3_2_c   : natural := 49; -- funct3 bit 2
  constant ctrl_ir_funct12_0_c  : natural := 50; -- funct12 bit 0
  constant ctrl_ir_funct12_1_c  : natural := 51; -- funct12 bit 1
  constant ctrl_ir_funct12_2_c  : natural := 52; -- funct12 bit 2
  constant ctrl_ir_funct12_3_c  : natural := 53; -- funct12 bit 3
  constant ctrl_ir_funct12_4_c  : natural := 54; -- funct12 bit 4
  constant ctrl_ir_funct12_5_c  : natural := 55; -- funct12 bit 5
  constant ctrl_ir_funct12_6_c  : natural := 56; -- funct12 bit 6
  constant ctrl_ir_funct12_7_c  : natural := 57; -- funct12 bit 7
  constant ctrl_ir_funct12_8_c  : natural := 58; -- funct12 bit 8
  constant ctrl_ir_funct12_9_c  : natural := 59; -- funct12 bit 9
  constant ctrl_ir_funct12_10_c : natural := 60; -- funct12 bit 10
  constant ctrl_ir_funct12_11_c : natural := 61; -- funct12 bit 11
  constant ctrl_ir_opcode7_0_c  : natural := 62; -- opcode7 bit 0
  constant ctrl_ir_opcode7_1_c  : natural := 63; -- opcode7 bit 1
  constant ctrl_ir_opcode7_2_c  : natural := 64; -- opcode7 bit 2
  constant ctrl_ir_opcode7_3_c  : natural := 65; -- opcode7 bit 3
  constant ctrl_ir_opcode7_4_c  : natural := 66; -- opcode7 bit 4
  constant ctrl_ir_opcode7_5_c  : natural := 67; -- opcode7 bit 5
  constant ctrl_ir_opcode7_6_c  : natural := 68; -- opcode7 bit 6
  -- CPU status --
  constant ctrl_sleep_c         : natural := 69; -- set when CPU is in sleep mode
  -- control bus size --
  constant ctrl_width_c         : natural := 70; -- control bus size
 
  -- Comparator Bus -------------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  constant cmp_equal_c : natural := 0;
  constant cmp_less_c  : natural := 1; -- for signed and unsigned comparisons
 
  -- RISC-V Opcode Layout -------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  constant instr_opcode_lsb_c  : natural :=  0; -- opcode bit 0
  constant instr_opcode_msb_c  : natural :=  6; -- opcode bit 6
  constant instr_rd_lsb_c      : natural :=  7; -- destination register address bit 0
  constant instr_rd_msb_c      : natural := 11; -- destination register address bit 4
  constant instr_funct3_lsb_c  : natural := 12; -- funct3 bit 0
  constant instr_funct3_msb_c  : natural := 14; -- funct3 bit 2
  constant instr_rs1_lsb_c     : natural := 15; -- source register 1 address bit 0
  constant instr_rs1_msb_c     : natural := 19; -- source register 1 address bit 4
  constant instr_rs2_lsb_c     : natural := 20; -- source register 2 address bit 0
  constant instr_rs2_msb_c     : natural := 24; -- source register 2 address bit 4
  constant instr_funct7_lsb_c  : natural := 25; -- funct7 bit 0
  constant instr_funct7_msb_c  : natural := 31; -- funct7 bit 6
  constant instr_funct12_lsb_c : natural := 20; -- funct12 bit 0
  constant instr_funct12_msb_c : natural := 31; -- funct12 bit 11
  constant instr_imm12_lsb_c   : natural := 20; -- immediate12 bit 0
  constant instr_imm12_msb_c   : natural := 31; -- immediate12 bit 11
  constant instr_imm20_lsb_c   : natural := 12; -- immediate20 bit 0
  constant instr_imm20_msb_c   : natural := 31; -- immediate20 bit 21
  constant instr_csr_id_lsb_c  : natural := 20; -- csr select bit 0
  constant instr_csr_id_msb_c  : natural := 31; -- csr select bit 11
  constant instr_funct5_lsb_c  : natural := 27; -- funct5 select bit 0
  constant instr_funct5_msb_c  : natural := 31; -- funct5 select bit 4
 
  -- RISC-V Opcodes -------------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- alu --
  constant opcode_lui_c    : std_ulogic_vector(6 downto 0) := "0110111"; -- load upper immediate
  constant opcode_auipc_c  : std_ulogic_vector(6 downto 0) := "0010111"; -- add upper immediate to PC
  constant opcode_alui_c   : std_ulogic_vector(6 downto 0) := "0010011"; -- ALU operation with immediate (operation via funct3 and funct7)
  constant opcode_alu_c    : std_ulogic_vector(6 downto 0) := "0110011"; -- ALU operation (operation via funct3 and funct7)
  -- control flow --
  constant opcode_jal_c    : std_ulogic_vector(6 downto 0) := "1101111"; -- jump and link
  constant opcode_jalr_c   : std_ulogic_vector(6 downto 0) := "1100111"; -- jump and link with register
  constant opcode_branch_c : std_ulogic_vector(6 downto 0) := "1100011"; -- branch (condition set via funct3)
  -- memory access --
  constant opcode_load_c   : std_ulogic_vector(6 downto 0) := "0000011"; -- load (data type via funct3)
  constant opcode_store_c  : std_ulogic_vector(6 downto 0) := "0100011"; -- store (data type via funct3)
  -- system/csr --
  constant opcode_fence_c  : std_ulogic_vector(6 downto 0) := "0001111"; -- fence / fence.i
  constant opcode_syscsr_c : std_ulogic_vector(6 downto 0) := "1110011"; -- system/csr access (type via funct3)
  -- atomic operations (A) --
  constant opcode_atomic_c : std_ulogic_vector(6 downto 0) := "0101111"; -- atomic operations (A extension)
 
  -- RISC-V Funct3 --------------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- control flow --
  constant funct3_beq_c    : std_ulogic_vector(2 downto 0) := "000"; -- branch if equal
  constant funct3_bne_c    : std_ulogic_vector(2 downto 0) := "001"; -- branch if not equal
  constant funct3_blt_c    : std_ulogic_vector(2 downto 0) := "100"; -- branch if less than
  constant funct3_bge_c    : std_ulogic_vector(2 downto 0) := "101"; -- branch if greater than or equal
  constant funct3_bltu_c   : std_ulogic_vector(2 downto 0) := "110"; -- branch if less than (unsigned)
  constant funct3_bgeu_c   : std_ulogic_vector(2 downto 0) := "111"; -- branch if greater than or equal (unsigned)
  -- memory access --
  constant funct3_lb_c     : std_ulogic_vector(2 downto 0) := "000"; -- load byte
  constant funct3_lh_c     : std_ulogic_vector(2 downto 0) := "001"; -- load half word
  constant funct3_lw_c     : std_ulogic_vector(2 downto 0) := "010"; -- load word
  constant funct3_lbu_c    : std_ulogic_vector(2 downto 0) := "100"; -- load byte (unsigned)
  constant funct3_lhu_c    : std_ulogic_vector(2 downto 0) := "101"; -- load half word (unsigned)
  constant funct3_sb_c     : std_ulogic_vector(2 downto 0) := "000"; -- store byte
  constant funct3_sh_c     : std_ulogic_vector(2 downto 0) := "001"; -- store half word
  constant funct3_sw_c     : std_ulogic_vector(2 downto 0) := "010"; -- store word
  -- alu --
  constant funct3_subadd_c : std_ulogic_vector(2 downto 0) := "000"; -- sub/add via funct7
  constant funct3_sll_c    : std_ulogic_vector(2 downto 0) := "001"; -- shift logical left
  constant funct3_slt_c    : std_ulogic_vector(2 downto 0) := "010"; -- set on less
  constant funct3_sltu_c   : std_ulogic_vector(2 downto 0) := "011"; -- set on less unsigned
  constant funct3_xor_c    : std_ulogic_vector(2 downto 0) := "100"; -- xor
  constant funct3_sr_c     : std_ulogic_vector(2 downto 0) := "101"; -- shift right via funct7
  constant funct3_or_c     : std_ulogic_vector(2 downto 0) := "110"; -- or
  constant funct3_and_c    : std_ulogic_vector(2 downto 0) := "111"; -- and
  -- system/csr --
  constant funct3_env_c    : std_ulogic_vector(2 downto 0) := "000"; -- ecall, ebreak, mret, wfi
  constant funct3_csrrw_c  : std_ulogic_vector(2 downto 0) := "001"; -- atomic r/w
  constant funct3_csrrs_c  : std_ulogic_vector(2 downto 0) := "010"; -- atomic read & set bit
  constant funct3_csrrc_c  : std_ulogic_vector(2 downto 0) := "011"; -- atomic read & clear bit
  constant funct3_csrrwi_c : std_ulogic_vector(2 downto 0) := "101"; -- atomic r/w immediate
  constant funct3_csrrsi_c : std_ulogic_vector(2 downto 0) := "110"; -- atomic read & set bit immediate
  constant funct3_csrrci_c : std_ulogic_vector(2 downto 0) := "111"; -- atomic read & clear bit immediate
  -- fence --
  constant funct3_fence_c  : std_ulogic_vector(2 downto 0) := "000"; -- fence - order IO/memory access (->NOP)
  constant funct3_fencei_c : std_ulogic_vector(2 downto 0) := "001"; -- fencei - instructon stream sync
 
  -- RISC-V Funct12 -------------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- system --
  constant funct12_ecall_c  : std_ulogic_vector(11 downto 0) := x"000"; -- ECALL
  constant funct12_ebreak_c : std_ulogic_vector(11 downto 0) := x"001"; -- EBREAK
  constant funct12_mret_c   : std_ulogic_vector(11 downto 0) := x"302"; -- MRET
  constant funct12_wfi_c    : std_ulogic_vector(11 downto 0) := x"105"; -- WFI
 
  -- RISC-V Funct5 --------------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- atomic operations --
  constant funct5_a_lr_c : std_ulogic_vector(4 downto 0) := "00010"; -- LR
  constant funct5_a_sc_c : std_ulogic_vector(4 downto 0) := "00011"; -- SC
 
  -- RISC-V CSR Addresses -------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- read/write CSRs --
  constant csr_mstatus_c        : std_ulogic_vector(11 downto 0) := x"300";
  constant csr_misa_c           : std_ulogic_vector(11 downto 0) := x"301";
  constant csr_mie_c            : std_ulogic_vector(11 downto 0) := x"304";
  constant csr_mtvec_c          : std_ulogic_vector(11 downto 0) := x"305";
  constant csr_mcounteren_c     : std_ulogic_vector(11 downto 0) := x"306";
  constant csr_mstatush_c       : std_ulogic_vector(11 downto 0) := x"310";
  --
  constant csr_mcountinhibit_c  : std_ulogic_vector(11 downto 0) := x"320";
  --
  constant csr_mhpmevent3_c     : std_ulogic_vector(11 downto 0) := x"323";
  constant csr_mhpmevent4_c     : std_ulogic_vector(11 downto 0) := x"324";
  constant csr_mhpmevent5_c     : std_ulogic_vector(11 downto 0) := x"325";
  constant csr_mhpmevent6_c     : std_ulogic_vector(11 downto 0) := x"326";
  constant csr_mhpmevent7_c     : std_ulogic_vector(11 downto 0) := x"327";
  constant csr_mhpmevent8_c     : std_ulogic_vector(11 downto 0) := x"328";
  constant csr_mhpmevent9_c     : std_ulogic_vector(11 downto 0) := x"329";
  constant csr_mhpmevent10_c    : std_ulogic_vector(11 downto 0) := x"32a";
  constant csr_mhpmevent11_c    : std_ulogic_vector(11 downto 0) := x"32b";
  constant csr_mhpmevent12_c    : std_ulogic_vector(11 downto 0) := x"32c";
  constant csr_mhpmevent13_c    : std_ulogic_vector(11 downto 0) := x"32d";
  constant csr_mhpmevent14_c    : std_ulogic_vector(11 downto 0) := x"32e";
  constant csr_mhpmevent15_c    : std_ulogic_vector(11 downto 0) := x"32f";
  constant csr_mhpmevent16_c    : std_ulogic_vector(11 downto 0) := x"330";
  constant csr_mhpmevent17_c    : std_ulogic_vector(11 downto 0) := x"331";
  constant csr_mhpmevent18_c    : std_ulogic_vector(11 downto 0) := x"332";
  constant csr_mhpmevent19_c    : std_ulogic_vector(11 downto 0) := x"333";
  constant csr_mhpmevent20_c    : std_ulogic_vector(11 downto 0) := x"334";
  constant csr_mhpmevent21_c    : std_ulogic_vector(11 downto 0) := x"335";
  constant csr_mhpmevent22_c    : std_ulogic_vector(11 downto 0) := x"336";
  constant csr_mhpmevent23_c    : std_ulogic_vector(11 downto 0) := x"337";
  constant csr_mhpmevent24_c    : std_ulogic_vector(11 downto 0) := x"338";
  constant csr_mhpmevent25_c    : std_ulogic_vector(11 downto 0) := x"339";
  constant csr_mhpmevent26_c    : std_ulogic_vector(11 downto 0) := x"33a";
  constant csr_mhpmevent27_c    : std_ulogic_vector(11 downto 0) := x"33b";
  constant csr_mhpmevent28_c    : std_ulogic_vector(11 downto 0) := x"33c";
  constant csr_mhpmevent29_c    : std_ulogic_vector(11 downto 0) := x"33d";
  constant csr_mhpmevent30_c    : std_ulogic_vector(11 downto 0) := x"33e";
  constant csr_mhpmevent31_c    : std_ulogic_vector(11 downto 0) := x"33f";
  --
  constant csr_mscratch_c       : std_ulogic_vector(11 downto 0) := x"340";
  constant csr_mepc_c           : std_ulogic_vector(11 downto 0) := x"341";
  constant csr_mcause_c         : std_ulogic_vector(11 downto 0) := x"342";
  constant csr_mtval_c          : std_ulogic_vector(11 downto 0) := x"343";
  constant csr_mip_c            : std_ulogic_vector(11 downto 0) := x"344";
  --
  constant csr_pmpcfg0_c        : std_ulogic_vector(11 downto 0) := x"3a0";
  constant csr_pmpcfg1_c        : std_ulogic_vector(11 downto 0) := x"3a1";
  constant csr_pmpcfg2_c        : std_ulogic_vector(11 downto 0) := x"3a2";
  constant csr_pmpcfg3_c        : std_ulogic_vector(11 downto 0) := x"3a3";
  constant csr_pmpcfg4_c        : std_ulogic_vector(11 downto 0) := x"3a4";
  constant csr_pmpcfg5_c        : std_ulogic_vector(11 downto 0) := x"3a5";
  constant csr_pmpcfg6_c        : std_ulogic_vector(11 downto 0) := x"3a6";
  constant csr_pmpcfg7_c        : std_ulogic_vector(11 downto 0) := x"3a7";
  constant csr_pmpcfg8_c        : std_ulogic_vector(11 downto 0) := x"3a8";
  constant csr_pmpcfg9_c        : std_ulogic_vector(11 downto 0) := x"3a9";
  constant csr_pmpcfg10_c       : std_ulogic_vector(11 downto 0) := x"3aa";
  constant csr_pmpcfg11_c       : std_ulogic_vector(11 downto 0) := x"3ab";
  constant csr_pmpcfg12_c       : std_ulogic_vector(11 downto 0) := x"3ac";
  constant csr_pmpcfg13_c       : std_ulogic_vector(11 downto 0) := x"3ad";
  constant csr_pmpcfg14_c       : std_ulogic_vector(11 downto 0) := x"3ae";
  constant csr_pmpcfg15_c       : std_ulogic_vector(11 downto 0) := x"3af";
  --
  constant csr_pmpaddr0_c       : std_ulogic_vector(11 downto 0) := x"3b0";
  constant csr_pmpaddr1_c       : std_ulogic_vector(11 downto 0) := x"3b1";
  constant csr_pmpaddr2_c       : std_ulogic_vector(11 downto 0) := x"3b2";
  constant csr_pmpaddr3_c       : std_ulogic_vector(11 downto 0) := x"3b3";
  constant csr_pmpaddr4_c       : std_ulogic_vector(11 downto 0) := x"3b4";
  constant csr_pmpaddr5_c       : std_ulogic_vector(11 downto 0) := x"3b5";
  constant csr_pmpaddr6_c       : std_ulogic_vector(11 downto 0) := x"3b6";
  constant csr_pmpaddr7_c       : std_ulogic_vector(11 downto 0) := x"3b7";
  constant csr_pmpaddr8_c       : std_ulogic_vector(11 downto 0) := x"3b8";
  constant csr_pmpaddr9_c       : std_ulogic_vector(11 downto 0) := x"3b9";
  constant csr_pmpaddr10_c      : std_ulogic_vector(11 downto 0) := x"3ba";
  constant csr_pmpaddr11_c      : std_ulogic_vector(11 downto 0) := x"3bb";
  constant csr_pmpaddr12_c      : std_ulogic_vector(11 downto 0) := x"3bc";
  constant csr_pmpaddr13_c      : std_ulogic_vector(11 downto 0) := x"3bd";
  constant csr_pmpaddr14_c      : std_ulogic_vector(11 downto 0) := x"3be";
  constant csr_pmpaddr15_c      : std_ulogic_vector(11 downto 0) := x"3bf";
  constant csr_pmpaddr16_c      : std_ulogic_vector(11 downto 0) := x"3c0";
  constant csr_pmpaddr17_c      : std_ulogic_vector(11 downto 0) := x"3c1";
  constant csr_pmpaddr18_c      : std_ulogic_vector(11 downto 0) := x"3c2";
  constant csr_pmpaddr19_c      : std_ulogic_vector(11 downto 0) := x"3c3";
  constant csr_pmpaddr20_c      : std_ulogic_vector(11 downto 0) := x"3c4";
  constant csr_pmpaddr21_c      : std_ulogic_vector(11 downto 0) := x"3c5";
  constant csr_pmpaddr22_c      : std_ulogic_vector(11 downto 0) := x"3c6";
  constant csr_pmpaddr23_c      : std_ulogic_vector(11 downto 0) := x"3c7";
  constant csr_pmpaddr24_c      : std_ulogic_vector(11 downto 0) := x"3c8";
  constant csr_pmpaddr25_c      : std_ulogic_vector(11 downto 0) := x"3c9";
  constant csr_pmpaddr26_c      : std_ulogic_vector(11 downto 0) := x"3ca";
  constant csr_pmpaddr27_c      : std_ulogic_vector(11 downto 0) := x"3cb";
  constant csr_pmpaddr28_c      : std_ulogic_vector(11 downto 0) := x"3cc";
  constant csr_pmpaddr29_c      : std_ulogic_vector(11 downto 0) := x"3cd";
  constant csr_pmpaddr30_c      : std_ulogic_vector(11 downto 0) := x"3ce";
  constant csr_pmpaddr31_c      : std_ulogic_vector(11 downto 0) := x"3cf";
  constant csr_pmpaddr32_c      : std_ulogic_vector(11 downto 0) := x"3d0";
  constant csr_pmpaddr33_c      : std_ulogic_vector(11 downto 0) := x"3d1";
  constant csr_pmpaddr34_c      : std_ulogic_vector(11 downto 0) := x"3d2";
  constant csr_pmpaddr35_c      : std_ulogic_vector(11 downto 0) := x"3d3";
  constant csr_pmpaddr36_c      : std_ulogic_vector(11 downto 0) := x"3d4";
  constant csr_pmpaddr37_c      : std_ulogic_vector(11 downto 0) := x"3d5";
  constant csr_pmpaddr38_c      : std_ulogic_vector(11 downto 0) := x"3d6";
  constant csr_pmpaddr39_c      : std_ulogic_vector(11 downto 0) := x"3d7";
  constant csr_pmpaddr40_c      : std_ulogic_vector(11 downto 0) := x"3d8";
  constant csr_pmpaddr41_c      : std_ulogic_vector(11 downto 0) := x"3d9";
  constant csr_pmpaddr42_c      : std_ulogic_vector(11 downto 0) := x"3da";
  constant csr_pmpaddr43_c      : std_ulogic_vector(11 downto 0) := x"3db";
  constant csr_pmpaddr44_c      : std_ulogic_vector(11 downto 0) := x"3dc";
  constant csr_pmpaddr45_c      : std_ulogic_vector(11 downto 0) := x"3dd";
  constant csr_pmpaddr46_c      : std_ulogic_vector(11 downto 0) := x"3de";
  constant csr_pmpaddr47_c      : std_ulogic_vector(11 downto 0) := x"3df";
  constant csr_pmpaddr48_c      : std_ulogic_vector(11 downto 0) := x"3e0";
  constant csr_pmpaddr49_c      : std_ulogic_vector(11 downto 0) := x"3e1";
  constant csr_pmpaddr50_c      : std_ulogic_vector(11 downto 0) := x"3e2";
  constant csr_pmpaddr51_c      : std_ulogic_vector(11 downto 0) := x"3e3";
  constant csr_pmpaddr52_c      : std_ulogic_vector(11 downto 0) := x"3e4";
  constant csr_pmpaddr53_c      : std_ulogic_vector(11 downto 0) := x"3e5";
  constant csr_pmpaddr54_c      : std_ulogic_vector(11 downto 0) := x"3e6";
  constant csr_pmpaddr55_c      : std_ulogic_vector(11 downto 0) := x"3e7";
  constant csr_pmpaddr56_c      : std_ulogic_vector(11 downto 0) := x"3e8";
  constant csr_pmpaddr57_c      : std_ulogic_vector(11 downto 0) := x"3e9";
  constant csr_pmpaddr58_c      : std_ulogic_vector(11 downto 0) := x"3ea";
  constant csr_pmpaddr59_c      : std_ulogic_vector(11 downto 0) := x"3eb";
  constant csr_pmpaddr60_c      : std_ulogic_vector(11 downto 0) := x"3ec";
  constant csr_pmpaddr61_c      : std_ulogic_vector(11 downto 0) := x"3ed";
  constant csr_pmpaddr62_c      : std_ulogic_vector(11 downto 0) := x"3ee";
  constant csr_pmpaddr63_c      : std_ulogic_vector(11 downto 0) := x"3ef";
  --
  constant csr_mcycle_c         : std_ulogic_vector(11 downto 0) := x"b00";
  constant csr_minstret_c       : std_ulogic_vector(11 downto 0) := x"b02";
  --
  constant csr_mhpmcounter3_c   : std_ulogic_vector(11 downto 0) := x"b03";
  constant csr_mhpmcounter4_c   : std_ulogic_vector(11 downto 0) := x"b04";
  constant csr_mhpmcounter5_c   : std_ulogic_vector(11 downto 0) := x"b05";
  constant csr_mhpmcounter6_c   : std_ulogic_vector(11 downto 0) := x"b06";
  constant csr_mhpmcounter7_c   : std_ulogic_vector(11 downto 0) := x"b07";
  constant csr_mhpmcounter8_c   : std_ulogic_vector(11 downto 0) := x"b08";
  constant csr_mhpmcounter9_c   : std_ulogic_vector(11 downto 0) := x"b09";
  constant csr_mhpmcounter10_c  : std_ulogic_vector(11 downto 0) := x"b0a";
  constant csr_mhpmcounter11_c  : std_ulogic_vector(11 downto 0) := x"b0b";
  constant csr_mhpmcounter12_c  : std_ulogic_vector(11 downto 0) := x"b0c";
  constant csr_mhpmcounter13_c  : std_ulogic_vector(11 downto 0) := x"b0d";
  constant csr_mhpmcounter14_c  : std_ulogic_vector(11 downto 0) := x"b0e";
  constant csr_mhpmcounter15_c  : std_ulogic_vector(11 downto 0) := x"b0f";
  constant csr_mhpmcounter16_c  : std_ulogic_vector(11 downto 0) := x"b10";
  constant csr_mhpmcounter17_c  : std_ulogic_vector(11 downto 0) := x"b11";
  constant csr_mhpmcounter18_c  : std_ulogic_vector(11 downto 0) := x"b12";
  constant csr_mhpmcounter19_c  : std_ulogic_vector(11 downto 0) := x"b13";
  constant csr_mhpmcounter20_c  : std_ulogic_vector(11 downto 0) := x"b14";
  constant csr_mhpmcounter21_c  : std_ulogic_vector(11 downto 0) := x"b15";
  constant csr_mhpmcounter22_c  : std_ulogic_vector(11 downto 0) := x"b16";
  constant csr_mhpmcounter23_c  : std_ulogic_vector(11 downto 0) := x"b17";
  constant csr_mhpmcounter24_c  : std_ulogic_vector(11 downto 0) := x"b18";
  constant csr_mhpmcounter25_c  : std_ulogic_vector(11 downto 0) := x"b19";
  constant csr_mhpmcounter26_c  : std_ulogic_vector(11 downto 0) := x"b1a";
  constant csr_mhpmcounter27_c  : std_ulogic_vector(11 downto 0) := x"b1b";
  constant csr_mhpmcounter28_c  : std_ulogic_vector(11 downto 0) := x"b1c";
  constant csr_mhpmcounter29_c  : std_ulogic_vector(11 downto 0) := x"b1d";
  constant csr_mhpmcounter30_c  : std_ulogic_vector(11 downto 0) := x"b1e";
  constant csr_mhpmcounter31_c  : std_ulogic_vector(11 downto 0) := x"b1f";
  --
  constant csr_mcycleh_c        : std_ulogic_vector(11 downto 0) := x"b80";
  constant csr_minstreth_c      : std_ulogic_vector(11 downto 0) := x"b82";
  --
  constant csr_mhpmcounter3h_c  : std_ulogic_vector(11 downto 0) := x"b83";
  constant csr_mhpmcounter4h_c  : std_ulogic_vector(11 downto 0) := x"b84";
  constant csr_mhpmcounter5h_c  : std_ulogic_vector(11 downto 0) := x"b85";
  constant csr_mhpmcounter6h_c  : std_ulogic_vector(11 downto 0) := x"b86";
  constant csr_mhpmcounter7h_c  : std_ulogic_vector(11 downto 0) := x"b87";
  constant csr_mhpmcounter8h_c  : std_ulogic_vector(11 downto 0) := x"b88";
  constant csr_mhpmcounter9h_c  : std_ulogic_vector(11 downto 0) := x"b89";
  constant csr_mhpmcounter10h_c : std_ulogic_vector(11 downto 0) := x"b8a";
  constant csr_mhpmcounter11h_c : std_ulogic_vector(11 downto 0) := x"b8b";
  constant csr_mhpmcounter12h_c : std_ulogic_vector(11 downto 0) := x"b8c";
  constant csr_mhpmcounter13h_c : std_ulogic_vector(11 downto 0) := x"b8d";
  constant csr_mhpmcounter14h_c : std_ulogic_vector(11 downto 0) := x"b8e";
  constant csr_mhpmcounter15h_c : std_ulogic_vector(11 downto 0) := x"b8f";
  constant csr_mhpmcounter16h_c : std_ulogic_vector(11 downto 0) := x"b90";
  constant csr_mhpmcounter17h_c : std_ulogic_vector(11 downto 0) := x"b91";
  constant csr_mhpmcounter18h_c : std_ulogic_vector(11 downto 0) := x"b92";
  constant csr_mhpmcounter19h_c : std_ulogic_vector(11 downto 0) := x"b93";
  constant csr_mhpmcounter20h_c : std_ulogic_vector(11 downto 0) := x"b94";
  constant csr_mhpmcounter21h_c : std_ulogic_vector(11 downto 0) := x"b95";
  constant csr_mhpmcounter22h_c : std_ulogic_vector(11 downto 0) := x"b96";
  constant csr_mhpmcounter23h_c : std_ulogic_vector(11 downto 0) := x"b97";
  constant csr_mhpmcounter24h_c : std_ulogic_vector(11 downto 0) := x"b98";
  constant csr_mhpmcounter25h_c : std_ulogic_vector(11 downto 0) := x"b99";
  constant csr_mhpmcounter26h_c : std_ulogic_vector(11 downto 0) := x"b9a";
  constant csr_mhpmcounter27h_c : std_ulogic_vector(11 downto 0) := x"b9b";
  constant csr_mhpmcounter28h_c : std_ulogic_vector(11 downto 0) := x"b9c";
  constant csr_mhpmcounter29h_c : std_ulogic_vector(11 downto 0) := x"b9d";
  constant csr_mhpmcounter30h_c : std_ulogic_vector(11 downto 0) := x"b9e";
  constant csr_mhpmcounter31h_c : std_ulogic_vector(11 downto 0) := x"b9f";
 
  -- read-only CSRs --
  constant csr_cycle_c          : std_ulogic_vector(11 downto 0) := x"c00";
  constant csr_time_c           : std_ulogic_vector(11 downto 0) := x"c01";
  constant csr_instret_c        : std_ulogic_vector(11 downto 0) := x"c02";
  --
  constant csr_hpmcounter3_c    : std_ulogic_vector(11 downto 0) := x"c03";
  constant csr_hpmcounter4_c    : std_ulogic_vector(11 downto 0) := x"c04";
  constant csr_hpmcounter5_c    : std_ulogic_vector(11 downto 0) := x"c05";
  constant csr_hpmcounter6_c    : std_ulogic_vector(11 downto 0) := x"c06";
  constant csr_hpmcounter7_c    : std_ulogic_vector(11 downto 0) := x"c07";
  constant csr_hpmcounter8_c    : std_ulogic_vector(11 downto 0) := x"c08";
  constant csr_hpmcounter9_c    : std_ulogic_vector(11 downto 0) := x"c09";
  constant csr_hpmcounter10_c   : std_ulogic_vector(11 downto 0) := x"c0a";
  constant csr_hpmcounter11_c   : std_ulogic_vector(11 downto 0) := x"c0b";
  constant csr_hpmcounter12_c   : std_ulogic_vector(11 downto 0) := x"c0c";
  constant csr_hpmcounter13_c   : std_ulogic_vector(11 downto 0) := x"c0d";
  constant csr_hpmcounter14_c   : std_ulogic_vector(11 downto 0) := x"c0e";
  constant csr_hpmcounter15_c   : std_ulogic_vector(11 downto 0) := x"c0f";
  constant csr_hpmcounter16_c   : std_ulogic_vector(11 downto 0) := x"c10";
  constant csr_hpmcounter17_c   : std_ulogic_vector(11 downto 0) := x"c11";
  constant csr_hpmcounter18_c   : std_ulogic_vector(11 downto 0) := x"c12";
  constant csr_hpmcounter19_c   : std_ulogic_vector(11 downto 0) := x"c13";
  constant csr_hpmcounter20_c   : std_ulogic_vector(11 downto 0) := x"c14";
  constant csr_hpmcounter21_c   : std_ulogic_vector(11 downto 0) := x"c15";
  constant csr_hpmcounter22_c   : std_ulogic_vector(11 downto 0) := x"c16";
  constant csr_hpmcounter23_c   : std_ulogic_vector(11 downto 0) := x"c17";
  constant csr_hpmcounter24_c   : std_ulogic_vector(11 downto 0) := x"c18";
  constant csr_hpmcounter25_c   : std_ulogic_vector(11 downto 0) := x"c19";
  constant csr_hpmcounter26_c   : std_ulogic_vector(11 downto 0) := x"c1a";
  constant csr_hpmcounter27_c   : std_ulogic_vector(11 downto 0) := x"c1b";
  constant csr_hpmcounter28_c   : std_ulogic_vector(11 downto 0) := x"c1c";
  constant csr_hpmcounter29_c   : std_ulogic_vector(11 downto 0) := x"c1d";
  constant csr_hpmcounter30_c   : std_ulogic_vector(11 downto 0) := x"c1e";
  constant csr_hpmcounter31_c   : std_ulogic_vector(11 downto 0) := x"c1f";
  --
  constant csr_cycleh_c         : std_ulogic_vector(11 downto 0) := x"c80";
  constant csr_timeh_c          : std_ulogic_vector(11 downto 0) := x"c81";
  constant csr_instreth_c       : std_ulogic_vector(11 downto 0) := x"c82";
  --
  constant csr_hpmcounter3h_c   : std_ulogic_vector(11 downto 0) := x"c83";
  constant csr_hpmcounter4h_c   : std_ulogic_vector(11 downto 0) := x"c84";
  constant csr_hpmcounter5h_c   : std_ulogic_vector(11 downto 0) := x"c85";
  constant csr_hpmcounter6h_c   : std_ulogic_vector(11 downto 0) := x"c86";
  constant csr_hpmcounter7h_c   : std_ulogic_vector(11 downto 0) := x"c87";
  constant csr_hpmcounter8h_c   : std_ulogic_vector(11 downto 0) := x"c88";
  constant csr_hpmcounter9h_c   : std_ulogic_vector(11 downto 0) := x"c89";
  constant csr_hpmcounter10h_c  : std_ulogic_vector(11 downto 0) := x"c8a";
  constant csr_hpmcounter11h_c  : std_ulogic_vector(11 downto 0) := x"c8b";
  constant csr_hpmcounter12h_c  : std_ulogic_vector(11 downto 0) := x"c8c";
  constant csr_hpmcounter13h_c  : std_ulogic_vector(11 downto 0) := x"c8d";
  constant csr_hpmcounter14h_c  : std_ulogic_vector(11 downto 0) := x"c8e";
  constant csr_hpmcounter15h_c  : std_ulogic_vector(11 downto 0) := x"c8f";
  constant csr_hpmcounter16h_c  : std_ulogic_vector(11 downto 0) := x"c90";
  constant csr_hpmcounter17h_c  : std_ulogic_vector(11 downto 0) := x"c91";
  constant csr_hpmcounter18h_c  : std_ulogic_vector(11 downto 0) := x"c92";
  constant csr_hpmcounter19h_c  : std_ulogic_vector(11 downto 0) := x"c93";
  constant csr_hpmcounter20h_c  : std_ulogic_vector(11 downto 0) := x"c94";
  constant csr_hpmcounter21h_c  : std_ulogic_vector(11 downto 0) := x"c95";
  constant csr_hpmcounter22h_c  : std_ulogic_vector(11 downto 0) := x"c96";
  constant csr_hpmcounter23h_c  : std_ulogic_vector(11 downto 0) := x"c97";
  constant csr_hpmcounter24h_c  : std_ulogic_vector(11 downto 0) := x"c98";
  constant csr_hpmcounter25h_c  : std_ulogic_vector(11 downto 0) := x"c99";
  constant csr_hpmcounter26h_c  : std_ulogic_vector(11 downto 0) := x"c9a";
  constant csr_hpmcounter27h_c  : std_ulogic_vector(11 downto 0) := x"c9b";
  constant csr_hpmcounter28h_c  : std_ulogic_vector(11 downto 0) := x"c9c";
  constant csr_hpmcounter29h_c  : std_ulogic_vector(11 downto 0) := x"c9d";
  constant csr_hpmcounter30h_c  : std_ulogic_vector(11 downto 0) := x"c9e";
  constant csr_hpmcounter31h_c  : std_ulogic_vector(11 downto 0) := x"c9f";
  --
  constant csr_mvendorid_c      : std_ulogic_vector(11 downto 0) := x"f11";
  constant csr_marchid_c        : std_ulogic_vector(11 downto 0) := x"f12";
  constant csr_mimpid_c         : std_ulogic_vector(11 downto 0) := x"f13";
  constant csr_mhartid_c        : std_ulogic_vector(11 downto 0) := x"f14";
 
  -- custom read-only CSRs --
  constant csr_mzext_c          : std_ulogic_vector(11 downto 0) := x"fc0";
 
  -- Co-Processor IDs -----------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  constant cp_sel_muldiv_c   : std_ulogic_vector(2 downto 0) := "000"; -- multiplication/division operations ('M' extension)
  constant cp_sel_atomic_c   : std_ulogic_vector(2 downto 0) := "001"; -- atomic operations; success/failure evaluation ('A' extension)
  constant cp_sel_bitmanip_c : std_ulogic_vector(2 downto 0) := "010"; -- bit manipulation ('B' extension)
  constant cp_sel_csr_rd_c   : std_ulogic_vector(2 downto 0) := "011"; -- CSR read access ('Zicsr' extension)
--constant cp_reserved_c     : std_ulogic_vector(2 downto 0) := "100"; -- reserved
--constant cp_reserved_c     : std_ulogic_vector(2 downto 0) := "101"; -- reserved
--constant cp_reserved_c     : std_ulogic_vector(2 downto 0) := "110"; -- reserved
--constant cp_reserved_c     : std_ulogic_vector(2 downto 0) := "111"; -- reserved
 
  -- ALU Function Codes ---------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- arithmetic core --
  constant alu_arith_cmd_addsub_c : std_ulogic := '0'; -- r.arith <= A +/- B
  constant alu_arith_cmd_slt_c    : std_ulogic := '1'; -- r.arith <= A < B
  -- logic core --
  constant alu_logic_cmd_movb_c   : std_ulogic_vector(1 downto 0) := "00"; -- r.logic <= B
  constant alu_logic_cmd_xor_c    : std_ulogic_vector(1 downto 0) := "01"; -- r.logic <= A xor B
  constant alu_logic_cmd_or_c     : std_ulogic_vector(1 downto 0) := "10"; -- r.logic <= A or B
  constant alu_logic_cmd_and_c    : std_ulogic_vector(1 downto 0) := "11"; -- r.logic <= A and B
  -- function select (actual alu result) --
  constant alu_func_cmd_arith_c   : std_ulogic_vector(1 downto 0) := "00"; -- r <= r.arith
  constant alu_func_cmd_logic_c   : std_ulogic_vector(1 downto 0) := "01"; -- r <= r.logic
  constant alu_func_cmd_shift_c   : std_ulogic_vector(1 downto 0) := "10"; -- r <= A <</>> B (iterative)
  constant alu_func_cmd_copro_c   : std_ulogic_vector(1 downto 0) := "11"; -- r <= CP result (iterative)
 
  -- Trap ID Codes --------------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- RISC-V compliant sync. exceptions --
  constant trap_ima_c    : std_ulogic_vector(5 downto 0) := "0" & "00000"; -- 0.0:  instruction misaligned
  constant trap_iba_c    : std_ulogic_vector(5 downto 0) := "0" & "00001"; -- 0.1:  instruction access fault
  constant trap_iil_c    : std_ulogic_vector(5 downto 0) := "0" & "00010"; -- 0.2:  illegal instruction
  constant trap_brk_c    : std_ulogic_vector(5 downto 0) := "0" & "00011"; -- 0.3:  breakpoint
  constant trap_lma_c    : std_ulogic_vector(5 downto 0) := "0" & "00100"; -- 0.4:  load address misaligned
  constant trap_lbe_c    : std_ulogic_vector(5 downto 0) := "0" & "00101"; -- 0.5:  load access fault
  constant trap_sma_c    : std_ulogic_vector(5 downto 0) := "0" & "00110"; -- 0.6:  store address misaligned
  constant trap_sbe_c    : std_ulogic_vector(5 downto 0) := "0" & "00111"; -- 0.7:  store access fault
  constant trap_uenv_c   : std_ulogic_vector(5 downto 0) := "0" & "01000"; -- 0.8:  environment call from u-mode
  constant trap_menv_c   : std_ulogic_vector(5 downto 0) := "0" & "01011"; -- 0.11: environment call from m-mode
  -- RISC-V compliant interrupts (async. exceptions) --
  constant trap_msi_c    : std_ulogic_vector(5 downto 0) := "1" & "00011"; -- 1.3:  machine software interrupt
  constant trap_mti_c    : std_ulogic_vector(5 downto 0) := "1" & "00111"; -- 1.7:  machine timer interrupt
  constant trap_mei_c    : std_ulogic_vector(5 downto 0) := "1" & "01011"; -- 1.11: machine external interrupt
  -- NEORV32-specific (custom) interrupts (async. exceptions) --
  constant trap_reset_c  : std_ulogic_vector(5 downto 0) := "1" & "00000"; -- 1.0:  hardware reset
  constant trap_firq0_c  : std_ulogic_vector(5 downto 0) := "1" & "10000"; -- 1.16: fast interrupt 0
  constant trap_firq1_c  : std_ulogic_vector(5 downto 0) := "1" & "10001"; -- 1.17: fast interrupt 1
  constant trap_firq2_c  : std_ulogic_vector(5 downto 0) := "1" & "10010"; -- 1.18: fast interrupt 2
  constant trap_firq3_c  : std_ulogic_vector(5 downto 0) := "1" & "10011"; -- 1.19: fast interrupt 3
  constant trap_firq4_c  : std_ulogic_vector(5 downto 0) := "1" & "10100"; -- 1.20: fast interrupt 4
  constant trap_firq5_c  : std_ulogic_vector(5 downto 0) := "1" & "10101"; -- 1.21: fast interrupt 5
  constant trap_firq6_c  : std_ulogic_vector(5 downto 0) := "1" & "10110"; -- 1.22: fast interrupt 6
  constant trap_firq7_c  : std_ulogic_vector(5 downto 0) := "1" & "10111"; -- 1.23: fast interrupt 7
  constant trap_firq8_c  : std_ulogic_vector(5 downto 0) := "1" & "11000"; -- 1.24: fast interrupt 8
  constant trap_firq9_c  : std_ulogic_vector(5 downto 0) := "1" & "11001"; -- 1.25: fast interrupt 9
  constant trap_firq10_c : std_ulogic_vector(5 downto 0) := "1" & "11010"; -- 1.26: fast interrupt 10
  constant trap_firq11_c : std_ulogic_vector(5 downto 0) := "1" & "11011"; -- 1.27: fast interrupt 11
  constant trap_firq12_c : std_ulogic_vector(5 downto 0) := "1" & "11100"; -- 1.28: fast interrupt 12
  constant trap_firq13_c : std_ulogic_vector(5 downto 0) := "1" & "11101"; -- 1.29: fast interrupt 13
  constant trap_firq14_c : std_ulogic_vector(5 downto 0) := "1" & "11110"; -- 1.30: fast interrupt 14
  constant trap_firq15_c : std_ulogic_vector(5 downto 0) := "1" & "11111"; -- 1.31: fast interrupt 15
 
  -- CPU Control Exception System -----------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  -- exception source bits --
  constant exception_iaccess_c   : natural :=  0; -- instrution access fault
  constant exception_iillegal_c  : natural :=  1; -- illegal instrution
  constant exception_ialign_c    : natural :=  2; -- instrution address misaligned
  constant exception_m_envcall_c : natural :=  3; -- ENV call from m-mode
  constant exception_u_envcall_c : natural :=  4; -- ENV call from u-mode
  constant exception_break_c     : natural :=  5; -- breakpoint
  constant exception_salign_c    : natural :=  6; -- store address misaligned
  constant exception_lalign_c    : natural :=  7; -- load address misaligned
  constant exception_saccess_c   : natural :=  8; -- store access fault
  constant exception_laccess_c   : natural :=  9; -- load access fault
  --
  constant exception_width_c     : natural := 10; -- length of this list in bits
  -- interrupt source bits --
  constant interrupt_msw_irq_c   : natural :=  0; -- machine software interrupt
  constant interrupt_mtime_irq_c : natural :=  1; -- machine timer interrupt
  constant interrupt_mext_irq_c  : natural :=  2; -- machine external interrupt
  constant interrupt_firq_0_c    : natural :=  3; -- fast interrupt channel 0
  constant interrupt_firq_1_c    : natural :=  4; -- fast interrupt channel 1
  constant interrupt_firq_2_c    : natural :=  5; -- fast interrupt channel 2
  constant interrupt_firq_3_c    : natural :=  6; -- fast interrupt channel 3
  constant interrupt_firq_4_c    : natural :=  7; -- fast interrupt channel 4
  constant interrupt_firq_5_c    : natural :=  8; -- fast interrupt channel 5
  constant interrupt_firq_6_c    : natural :=  9; -- fast interrupt channel 6
  constant interrupt_firq_7_c    : natural := 10; -- fast interrupt channel 7
  constant interrupt_firq_8_c    : natural := 11; -- fast interrupt channel 8
  constant interrupt_firq_9_c    : natural := 12; -- fast interrupt channel 9
  constant interrupt_firq_10_c   : natural := 13; -- fast interrupt channel 10
  constant interrupt_firq_11_c   : natural := 14; -- fast interrupt channel 11
  constant interrupt_firq_12_c   : natural := 15; -- fast interrupt channel 12
  constant interrupt_firq_13_c   : natural := 16; -- fast interrupt channel 13
  constant interrupt_firq_14_c   : natural := 17; -- fast interrupt channel 14
  constant interrupt_firq_15_c   : natural := 18; -- fast interrupt channel 15
  --
  constant interrupt_width_c     : natural := 19; -- length of this list in bits
 
  -- CPU Privilege Modes --------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  constant priv_mode_m_c : std_ulogic_vector(1 downto 0) := "11"; -- machine mode
  constant priv_mode_u_c : std_ulogic_vector(1 downto 0) := "00"; -- user mode
 
  -- HPM Event System -----------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  constant hpmcnt_event_cy_c      : natural := 0;  -- Active cycle
  constant hpmcnt_event_never_c   : natural := 1;
  constant hpmcnt_event_ir_c      : natural := 2;  -- Retired instruction
  constant hpmcnt_event_cir_c     : natural := 3;  -- Retired compressed instruction
  constant hpmcnt_event_wait_if_c : natural := 4;  -- Instruction fetch memory wait cycle
  constant hpmcnt_event_wait_ii_c : natural := 5;  -- Instruction issue wait cycle
  constant hpmcnt_event_wait_mc_c : natural := 6;  -- Multi-cycle ALU-operation wait cycle
  constant hpmcnt_event_load_c    : natural := 7;  -- Load operation
  constant hpmcnt_event_store_c   : natural := 8;  -- Store operation
  constant hpmcnt_event_wait_ls_c : natural := 9;  -- Load/store memory wait cycle
  constant hpmcnt_event_jump_c    : natural := 10; -- Unconditional jump
  constant hpmcnt_event_branch_c  : natural := 11; -- Conditional branch (taken or not taken)
  constant hpmcnt_event_tbranch_c : natural := 12; -- Conditional taken branch
  constant hpmcnt_event_trap_c    : natural := 13; -- Entered trap
  constant hpmcnt_event_illegal_c : natural := 14; -- Illegal instruction exception
  --
  constant hpmcnt_event_size_c    : natural := 15; -- length of this list
 
  -- Clock Generator ------------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  constant clk_div2_c    : natural := 0;
  constant clk_div4_c    : natural := 1;
  constant clk_div8_c    : natural := 2;
  constant clk_div64_c   : natural := 3;
  constant clk_div128_c  : natural := 4;
  constant clk_div1024_c : natural := 5;
  constant clk_div2048_c : natural := 6;
  constant clk_div4096_c : natural := 7;
 
  -- Component: NEORV32 Processor Top Entity ------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_top
    generic (
      -- General --
      CLOCK_FREQUENCY              : natural := 0;      -- clock frequency of clk_i in Hz
      BOOTLOADER_EN                : boolean := true;   -- implement processor-internal bootloader?
      USER_CODE                    : std_ulogic_vector(31 downto 0) := x"00000000"; -- custom user code
      HW_THREAD_ID                 : natural := 0;      -- hardware thread id (32-bit)
      -- RISC-V CPU Extensions --
      CPU_EXTENSION_RISCV_A        : boolean := false;  -- implement atomic extension?
      CPU_EXTENSION_RISCV_B        : boolean := false;  -- implement bit manipulation extensions?
      CPU_EXTENSION_RISCV_C        : boolean := false;  -- implement compressed extension?
      CPU_EXTENSION_RISCV_E        : boolean := false;  -- implement embedded RF extension?
      CPU_EXTENSION_RISCV_M        : boolean := false;  -- implement muld/div extension?
      CPU_EXTENSION_RISCV_U        : boolean := false;  -- implement user mode extension?
      CPU_EXTENSION_RISCV_Zicsr    : boolean := true;   -- implement CSR system?
      CPU_EXTENSION_RISCV_Zifencei : boolean := false;  -- implement instruction stream sync.?
      -- Extension Options --
      FAST_MUL_EN                  : boolean := false;  -- use DSPs for M extension's multiplier
      FAST_SHIFT_EN                : boolean := false;  -- use barrel shifter for shift operations
      -- Physical Memory Protection (PMP) --
      PMP_NUM_REGIONS              : natural := 0;      -- number of regions (0..64)
      PMP_MIN_GRANULARITY          : natural := 64*1024; -- minimal region granularity in bytes, has to be a power of 2, min 8 bytes
      -- Hardware Performance Monitors (HPM) --
      HPM_NUM_CNTS                 : natural := 0;      -- number of implemented HPM counters (0..29)
      -- Internal Instruction memory --
      MEM_INT_IMEM_EN              : boolean := true;   -- implement processor-internal instruction memory
      MEM_INT_IMEM_SIZE            : natural := 16*1024; -- size of processor-internal instruction memory in bytes
      MEM_INT_IMEM_ROM             : boolean := false;  -- implement processor-internal instruction memory as ROM
      -- Internal Data memory --
      MEM_INT_DMEM_EN              : boolean := true;   -- implement processor-internal data memory
      MEM_INT_DMEM_SIZE            : natural := 8*1024; -- size of processor-internal data memory in bytes
      -- Internal Cache memory --
      ICACHE_EN                    : boolean := false;  -- implement instruction cache
      ICACHE_NUM_BLOCKS            : natural := 4;      -- i-cache: number of blocks (min 1), has to be a power of 2
      ICACHE_BLOCK_SIZE            : natural := 64;     -- i-cache: block size in bytes (min 4), has to be a power of 2
      ICACHE_ASSOCIATIVITY         : natural := 1;      -- i-cache: associativity / number of sets (1=direct_mapped), has to be a power of 2
      -- External memory interface --
      MEM_EXT_EN                   : boolean := false;  -- implement external memory bus interface?
      -- Processor peripherals --
      IO_GPIO_EN                   : boolean := true;   -- implement general purpose input/output port unit (GPIO)?
      IO_MTIME_EN                  : boolean := true;   -- implement machine system timer (MTIME)?
      IO_UART_EN                   : boolean := true;   -- implement universal asynchronous receiver/transmitter (UART)?
      IO_SPI_EN                    : boolean := true;   -- implement serial peripheral interface (SPI)?
      IO_TWI_EN                    : boolean := true;   -- implement two-wire interface (TWI)?
      IO_PWM_EN                    : boolean := true;   -- implement pulse-width modulation unit (PWM)?
      IO_WDT_EN                    : boolean := true;   -- implement watch dog timer (WDT)?
      IO_TRNG_EN                   : boolean := false;  -- implement true random number generator (TRNG)?
      IO_CFS_EN                    : boolean := false;  -- implement custom functions subsystem (CFS)?
      IO_CFS_CONFIG                : std_ulogic_vector(31 downto 0) := x"00000000"; -- custom CFS configuration generic
      IO_NCO_EN                    : boolean := true    -- implement numerically-controlled oscillator (NCO)?
    );
    port (
      -- Global control --
      clk_i       : in  std_ulogic := '0'; -- global clock, rising edge
      rstn_i      : in  std_ulogic := '0'; -- global reset, low-active, async
      -- Wishbone bus interface (available if MEM_EXT_EN = true) --
      wb_tag_o    : out std_ulogic_vector(02 downto 0); -- tag
      wb_adr_o    : out std_ulogic_vector(31 downto 0); -- address
      wb_dat_i    : in  std_ulogic_vector(31 downto 0) := (others => '0'); -- read data
      wb_dat_o    : out std_ulogic_vector(31 downto 0); -- write data
      wb_we_o     : out std_ulogic; -- read/write
      wb_sel_o    : out std_ulogic_vector(03 downto 0); -- byte enable
      wb_stb_o    : out std_ulogic; -- strobe
      wb_cyc_o    : out std_ulogic; -- valid cycle
      wb_lock_o   : out std_ulogic; -- locked/exclusive bus access
      wb_ack_i    : in  std_ulogic := '0'; -- transfer acknowledge
      wb_err_i    : in  std_ulogic := '0'; -- transfer error
      -- Advanced memory control signals (available if MEM_EXT_EN = true) --
      fence_o     : out std_ulogic; -- indicates an executed FENCE operation
      fencei_o    : out std_ulogic; -- indicates an executed FENCEI operation
      -- GPIO (available if IO_GPIO_EN = true) --
      gpio_o      : out std_ulogic_vector(31 downto 0); -- parallel output
      gpio_i      : in  std_ulogic_vector(31 downto 0) := (others => '0'); -- parallel input
      -- UART (available if IO_UART_EN = true) --
      uart_txd_o  : out std_ulogic; -- UART send data
      uart_rxd_i  : in  std_ulogic := '0'; -- UART receive data
      -- SPI (available if IO_SPI_EN = true) --
      spi_sck_o   : out std_ulogic; -- SPI serial clock
      spi_sdo_o   : out std_ulogic; -- controller data out, peripheral data in
      spi_sdi_i   : in  std_ulogic := '0'; -- controller data in, peripheral data out
      spi_csn_o   : out std_ulogic_vector(07 downto 0); -- SPI CS
      -- TWI (available if IO_TWI_EN = true) --
      twi_sda_io  : inout std_logic; -- twi serial data line
      twi_scl_io  : inout std_logic; -- twi serial clock line
      -- PWM (available if IO_PWM_EN = true) --
      pwm_o       : out std_ulogic_vector(03 downto 0); -- pwm channels
      -- Custom Functions Subsystem IO --
      cfs_in_i    : in  std_ulogic_vector(31 downto 0) := (others => '0'); -- custom CSF inputs
      cfs_out_o   : out std_ulogic_vector(31 downto 0); -- custom CSF outputs
      -- NCO output (available if IO_NCO_EN = true) --
      nco_o       : out std_ulogic_vector(02 downto 0); -- numerically-controlled oscillator channels
      -- system time input from external MTIME (available if IO_MTIME_EN = false) --
      mtime_i     : in  std_ulogic_vector(63 downto 0) := (others => '0'); -- current system time
      -- Interrupts --
      soc_firq_i  : in  std_ulogic_vector(7 downto 0) := (others => '0'); -- fast interrupt channels
      mtime_irq_i : in  std_ulogic := '0'; -- machine timer interrupt, available if IO_MTIME_EN = false
      msw_irq_i   : in  std_ulogic := '0'; -- machine software interrupt
      mext_irq_i  : in  std_ulogic := '0'  -- machine external interrupt
    );
  end component;
 
  -- Component: CPU Top Entity --------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_cpu
    generic (
      -- General --
      HW_THREAD_ID                 : natural := 0;     -- hardware thread id (32-bit)
      CPU_BOOT_ADDR                : std_ulogic_vector(31 downto 0) := x"00000000"; -- cpu boot address
      BUS_TIMEOUT                  : natural := 63;    -- cycles after an UNACKNOWLEDGED bus access triggers a bus fault exception
      -- RISC-V CPU Extensions --
      CPU_EXTENSION_RISCV_A        : boolean := false; -- implement atomic extension?
      CPU_EXTENSION_RISCV_B        : boolean := false; -- implement bit manipulation extensions?
      CPU_EXTENSION_RISCV_C        : boolean := false; -- implement compressed extension?
      CPU_EXTENSION_RISCV_E        : boolean := false; -- implement embedded RF extension?
      CPU_EXTENSION_RISCV_M        : boolean := false; -- implement muld/div extension?
      CPU_EXTENSION_RISCV_U        : boolean := false; -- implement user mode extension?
      CPU_EXTENSION_RISCV_Zicsr    : boolean := true;  -- implement CSR system?
      CPU_EXTENSION_RISCV_Zifencei : boolean := false; -- implement instruction stream sync.?
      -- Extension Options --
      FAST_MUL_EN                  : boolean := false; -- use DSPs for M extension's multiplier
      FAST_SHIFT_EN                : boolean := false; -- use barrel shifter for shift operations
      -- Physical Memory Protection (PMP) --
      PMP_NUM_REGIONS              : natural := 0; -- number of regions (0..64)
      PMP_MIN_GRANULARITY          : natural := 64*1024; -- minimal region granularity in bytes, has to be a power of 2, min 8 bytes
      -- Hardware Performance Monitors (HPM) --
      HPM_NUM_CNTS                 : natural := 0      -- number of implemented HPM counters (0..29)
    );
    port (
      -- global control --
      clk_i          : in  std_ulogic := '0'; -- global clock, rising edge
      rstn_i         : in  std_ulogic := '0'; -- global reset, low-active, async
      sleep_o        : out std_ulogic; -- cpu is in sleep mode when set
      -- instruction bus interface --
      i_bus_addr_o   : out std_ulogic_vector(data_width_c-1 downto 0); -- bus access address
      i_bus_rdata_i  : in  std_ulogic_vector(data_width_c-1 downto 0) := (others => '0'); -- bus read data
      i_bus_wdata_o  : out std_ulogic_vector(data_width_c-1 downto 0); -- bus write data
      i_bus_ben_o    : out std_ulogic_vector(03 downto 0); -- byte enable
      i_bus_we_o     : out std_ulogic; -- write enable
      i_bus_re_o     : out std_ulogic; -- read enable
      i_bus_cancel_o : out std_ulogic; -- cancel current bus transaction
      i_bus_ack_i    : in  std_ulogic := '0'; -- bus transfer acknowledge
      i_bus_err_i    : in  std_ulogic := '0'; -- bus transfer error
      i_bus_fence_o  : out std_ulogic; -- executed FENCEI operation
      i_bus_priv_o   : out std_ulogic_vector(1 downto 0); -- privilege level
      i_bus_lock_o   : out std_ulogic; -- locked/exclusive access
      -- data bus interface --
      d_bus_addr_o   : out std_ulogic_vector(data_width_c-1 downto 0); -- bus access address
      d_bus_rdata_i  : in  std_ulogic_vector(data_width_c-1 downto 0) := (others => '0'); -- bus read data
      d_bus_wdata_o  : out std_ulogic_vector(data_width_c-1 downto 0); -- bus write data
      d_bus_ben_o    : out std_ulogic_vector(03 downto 0); -- byte enable
      d_bus_we_o     : out std_ulogic; -- write enable
      d_bus_re_o     : out std_ulogic; -- read enable
      d_bus_cancel_o : out std_ulogic; -- cancel current bus transaction
      d_bus_ack_i    : in  std_ulogic := '0'; -- bus transfer acknowledge
      d_bus_err_i    : in  std_ulogic := '0'; -- bus transfer error
      d_bus_fence_o  : out std_ulogic; -- executed FENCE operation
      d_bus_priv_o   : out std_ulogic_vector(1 downto 0); -- privilege level
      d_bus_lock_o   : out std_ulogic; -- locked/exclusive access
      -- system time input from MTIME --
      time_i         : in  std_ulogic_vector(63 downto 0) := (others => '0'); -- current system time
      -- interrupts (risc-v compliant) --
      msw_irq_i      : in  std_ulogic := '0'; -- machine software interrupt
      mext_irq_i     : in  std_ulogic := '0'; -- machine external interrupt
      mtime_irq_i    : in  std_ulogic := '0'; -- machine timer interrupt
      -- fast interrupts (custom) --
      firq_i         : in  std_ulogic_vector(15 downto 0) := (others => '0');
      firq_ack_o     : out std_ulogic_vector(15 downto 0)
    );
  end component;
 
  -- Component: CPU Control -----------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_cpu_control
    generic (
      -- General --
      HW_THREAD_ID                 : natural := 0;     -- hardware thread id (32-bit)
      CPU_BOOT_ADDR                : std_ulogic_vector(31 downto 0):= x"00000000"; -- cpu boot address
      -- RISC-V CPU Extensions --
      CPU_EXTENSION_RISCV_A        : boolean := false; -- implement atomic extension?
      CPU_EXTENSION_RISCV_B        : boolean := false; -- implement bit manipulation extensions?
      CPU_EXTENSION_RISCV_C        : boolean := false; -- implement compressed extension?
      CPU_EXTENSION_RISCV_E        : boolean := false; -- implement embedded RF extension?
      CPU_EXTENSION_RISCV_M        : boolean := false; -- implement muld/div extension?
      CPU_EXTENSION_RISCV_U        : boolean := false; -- implement user mode extension?
      CPU_EXTENSION_RISCV_Zicsr    : boolean := true;  -- implement CSR system?
      CPU_EXTENSION_RISCV_Zifencei : boolean := false; -- implement instruction stream sync.?
      -- Physical memory protection (PMP) --
      PMP_NUM_REGIONS              : natural := 0; -- number of regions (0..64)
      PMP_MIN_GRANULARITY          : natural := 64*1024; -- minimal region granularity in bytes, has to be a power of 2, min 8 bytes
      -- Hardware Performance Monitors (HPM) --
      HPM_NUM_CNTS                 : natural := 0      -- number of implemented HPM counters (0..29)
    );
    port (
      -- global control --
      clk_i         : in  std_ulogic; -- global clock, rising edge
      rstn_i        : in  std_ulogic; -- global reset, low-active, async
      ctrl_o        : out std_ulogic_vector(ctrl_width_c-1 downto 0); -- main control bus
      -- status input --
      alu_wait_i    : in  std_ulogic; -- wait for ALU
      bus_i_wait_i  : in  std_ulogic; -- wait for bus
      bus_d_wait_i  : in  std_ulogic; -- wait for bus
      -- data input --
      instr_i       : in  std_ulogic_vector(data_width_c-1 downto 0); -- instruction
      cmp_i         : in  std_ulogic_vector(1 downto 0); -- comparator status
      alu_add_i     : in  std_ulogic_vector(data_width_c-1 downto 0); -- ALU address result
      rs1_i       : in  std_ulogic_vector(data_width_c-1 downto 0); -- rf source 1
      -- data output --
      imm_o         : out std_ulogic_vector(data_width_c-1 downto 0); -- immediate
      fetch_pc_o    : out std_ulogic_vector(data_width_c-1 downto 0); -- PC for instruction fetch
      curr_pc_o     : out std_ulogic_vector(data_width_c-1 downto 0); -- current PC (corresponding to current instruction)
      csr_rdata_o   : out std_ulogic_vector(data_width_c-1 downto 0); -- CSR read data
      -- interrupts (risc-v compliant) --
      msw_irq_i     : in  std_ulogic; -- machine software interrupt
      mext_irq_i    : in  std_ulogic; -- machine external interrupt
      mtime_irq_i   : in  std_ulogic; -- machine timer interrupt
      -- fast interrupts (custom) --
      firq_i        : in  std_ulogic_vector(15 downto 0);
      firq_ack_o    : out std_ulogic_vector(15 downto 0);
      -- system time input from MTIME --
      time_i        : in  std_ulogic_vector(63 downto 0); -- current system time
      -- physical memory protection --
      pmp_addr_o    : out pmp_addr_if_t; -- addresses
      pmp_ctrl_o    : out pmp_ctrl_if_t; -- configs
      -- bus access exceptions --
      mar_i         : in  std_ulogic_vector(data_width_c-1 downto 0); -- memory address register
      ma_instr_i    : in  std_ulogic; -- misaligned instruction address
      ma_load_i     : in  std_ulogic; -- misaligned load data address
      ma_store_i    : in  std_ulogic; -- misaligned store data address
      be_instr_i    : in  std_ulogic; -- bus error on instruction access
      be_load_i     : in  std_ulogic; -- bus error on load data access
      be_store_i    : in  std_ulogic  -- bus error on store data access
    );
  end component;
 
  -- Component: CPU Register File -----------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_cpu_regfile
    generic (
      CPU_EXTENSION_RISCV_E : boolean := false -- implement embedded RF extension?
    );
    port (
      -- global control --
      clk_i  : in  std_ulogic; -- global clock, rising edge
      ctrl_i : in  std_ulogic_vector(ctrl_width_c-1 downto 0); -- main control bus
      -- data input --
      mem_i  : in  std_ulogic_vector(data_width_c-1 downto 0); -- memory read data
      alu_i  : in  std_ulogic_vector(data_width_c-1 downto 0); -- ALU result
      -- data output --
      rs1_o  : out std_ulogic_vector(data_width_c-1 downto 0); -- operand 1
      rs2_o  : out std_ulogic_vector(data_width_c-1 downto 0); -- operand 2
      cmp_o  : out std_ulogic_vector(1 downto 0) -- comparator status
    );
  end component;
 
  -- Component: CPU ALU ---------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_cpu_alu
    generic (
      CPU_EXTENSION_RISCV_M : boolean := true; -- implement muld/div extension?
      FAST_SHIFT_EN         : boolean := false -- use barrel shifter for shift operations
    );
    port (
      -- global control --
      clk_i       : in  std_ulogic; -- global clock, rising edge
      rstn_i      : in  std_ulogic; -- global reset, low-active, async
      ctrl_i      : in  std_ulogic_vector(ctrl_width_c-1 downto 0); -- main control bus
      -- data input --
      rs1_i       : in  std_ulogic_vector(data_width_c-1 downto 0); -- rf source 1
      rs2_i       : in  std_ulogic_vector(data_width_c-1 downto 0); -- rf source 2
      pc2_i       : in  std_ulogic_vector(data_width_c-1 downto 0); -- delayed PC
      imm_i       : in  std_ulogic_vector(data_width_c-1 downto 0); -- immediate
      -- data output --
      res_o       : out std_ulogic_vector(data_width_c-1 downto 0); -- ALU result
      add_o       : out std_ulogic_vector(data_width_c-1 downto 0); -- address computation result
      -- co-processor interface --
      cp_start_o  : out std_ulogic_vector(7 downto 0); -- trigger co-processor i
      cp_valid_i  : in  std_ulogic_vector(7 downto 0); -- co-processor i done
      cp_result_i : in  cp_data_if_t; -- co-processor result
      -- status --
      wait_o      : out std_ulogic -- busy due to iterative processing units
    );
  end component;
 
  -- Component: CPU Co-Processor MULDIV ('M' extension) -------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_cpu_cp_muldiv
    generic (
      FAST_MUL_EN : boolean := false -- use DSPs for faster multiplication
    );
    port (
      -- global control --
      clk_i   : in  std_ulogic; -- global clock, rising edge
      rstn_i  : in  std_ulogic; -- global reset, low-active, async
      ctrl_i  : in  std_ulogic_vector(ctrl_width_c-1 downto 0); -- main control bus
      start_i : in  std_ulogic; -- trigger operation
      -- data input --
      rs1_i   : in  std_ulogic_vector(data_width_c-1 downto 0); -- rf source 1
      rs2_i   : in  std_ulogic_vector(data_width_c-1 downto 0); -- rf source 2
      -- result and status --
      res_o   : out std_ulogic_vector(data_width_c-1 downto 0); -- operation result
      valid_o : out std_ulogic -- data output valid
    );
  end component;
 
  -- Component: CPU Co-Processor Bit Manipulation ('B' extension) ---------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_cpu_cp_bitmanip
    port (
      -- global control --
      clk_i   : in  std_ulogic; -- global clock, rising edge
      rstn_i  : in  std_ulogic; -- global reset, low-active, async
      ctrl_i  : in  std_ulogic_vector(ctrl_width_c-1 downto 0); -- main control bus
      start_i : in  std_ulogic; -- trigger operation
      -- data input --
      cmp_i   : in  std_ulogic_vector(1 downto 0); -- comparator status
      rs1_i   : in  std_ulogic_vector(data_width_c-1 downto 0); -- rf source 1
      rs2_i   : in  std_ulogic_vector(data_width_c-1 downto 0); -- rf source 2
      -- result and status --
      res_o   : out std_ulogic_vector(data_width_c-1 downto 0); -- operation result
      valid_o : out std_ulogic -- data output valid
    );
  end component;
 
  -- Component: CPU Bus Interface -----------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_cpu_bus
    generic (
      CPU_EXTENSION_RISCV_C : boolean := true;  -- implement compressed extension?
      -- Physical memory protection (PMP) --
      PMP_NUM_REGIONS       : natural := 0;       -- number of regions (0..64)
      PMP_MIN_GRANULARITY   : natural := 64*1024; -- minimal region granularity in bytes, has to be a power of 2, min 8 bytes
      -- Bus Timeout --
      BUS_TIMEOUT           : natural := 63     -- cycles after an UNACKNOWLEDGED bus access triggers a bus fault exception
    );
    port (
      -- global control --
      clk_i          : in  std_ulogic; -- global clock, rising edge
      rstn_i      : in  std_ulogic := '0'; -- global reset, low-active, async
      ctrl_i         : in  std_ulogic_vector(ctrl_width_c-1 downto 0); -- main control bus
      -- cpu instruction fetch interface --
      fetch_pc_i     : in  std_ulogic_vector(data_width_c-1 downto 0); -- PC for instruction fetch
      instr_o        : out std_ulogic_vector(data_width_c-1 downto 0); -- instruction
      i_wait_o       : out std_ulogic; -- wait for fetch to complete
      --
      ma_instr_o     : out std_ulogic; -- misaligned instruction address
      be_instr_o     : out std_ulogic; -- bus error on instruction access
      -- cpu data access interface --
      addr_i         : in  std_ulogic_vector(data_width_c-1 downto 0); -- ALU result -> access address
      wdata_i        : in  std_ulogic_vector(data_width_c-1 downto 0); -- write data
      rdata_o        : out std_ulogic_vector(data_width_c-1 downto 0); -- read data
      mar_o          : out std_ulogic_vector(data_width_c-1 downto 0); -- current memory address register
      d_wait_o       : out std_ulogic; -- wait for access to complete
      --
      ma_load_o      : out std_ulogic; -- misaligned load data address
      ma_store_o     : out std_ulogic; -- misaligned store data address
      be_load_o      : out std_ulogic; -- bus error on load data access
      be_store_o     : out std_ulogic; -- bus error on store data access
      -- physical memory protection --
      pmp_addr_i     : in  pmp_addr_if_t; -- addresses
      pmp_ctrl_i     : in  pmp_ctrl_if_t; -- configs
      -- instruction bus --
      i_bus_addr_o   : out std_ulogic_vector(data_width_c-1 downto 0); -- bus access address
      i_bus_rdata_i  : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus read data
      i_bus_wdata_o  : out std_ulogic_vector(data_width_c-1 downto 0); -- bus write data
      i_bus_ben_o    : out std_ulogic_vector(03 downto 0); -- byte enable
      i_bus_we_o     : out std_ulogic; -- write enable
      i_bus_re_o     : out std_ulogic; -- read enable
      i_bus_cancel_o : out std_ulogic; -- cancel current bus transaction
      i_bus_ack_i    : in  std_ulogic; -- bus transfer acknowledge
      i_bus_err_i    : in  std_ulogic; -- bus transfer error
      i_bus_fence_o  : out std_ulogic; -- fence operation
      i_bus_lock_o   : out std_ulogic; -- locked/exclusive access
      -- data bus --
      d_bus_addr_o   : out std_ulogic_vector(data_width_c-1 downto 0); -- bus access address
      d_bus_rdata_i  : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus read data
      d_bus_wdata_o  : out std_ulogic_vector(data_width_c-1 downto 0); -- bus write data
      d_bus_ben_o    : out std_ulogic_vector(03 downto 0); -- byte enable
      d_bus_we_o     : out std_ulogic; -- write enable
      d_bus_re_o     : out std_ulogic; -- read enable
      d_bus_cancel_o : out std_ulogic; -- cancel current bus transaction
      d_bus_ack_i    : in  std_ulogic; -- bus transfer acknowledge
      d_bus_err_i    : in  std_ulogic; -- bus transfer error
      d_bus_fence_o  : out std_ulogic; -- fence operation
      d_bus_lock_o   : out std_ulogic  -- locked/exclusive access
    );
  end component;
 
  -- Component: CPU Instruction Cache -------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_icache
    generic (
      ICACHE_NUM_BLOCKS : natural := 4;  -- number of blocks (min 1), has to be a power of 2
      ICACHE_BLOCK_SIZE : natural := 16; -- block size in bytes (min 4), has to be a power of 2
      ICACHE_NUM_SETS   : natural := 1   -- associativity / number of sets (1=direct_mapped), has to be a power of 2
    );
    port (
      -- global control --
      clk_i         : in  std_ulogic; -- global clock, rising edge
      rstn_i        : in  std_ulogic; -- global reset, low-active, async
      clear_i       : in  std_ulogic; -- cache clear
      -- host controller interface --
      host_addr_i   : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus access address
      host_rdata_o  : out std_ulogic_vector(data_width_c-1 downto 0); -- bus read data
      host_wdata_i  : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus write data
      host_ben_i    : in  std_ulogic_vector(03 downto 0); -- byte enable
      host_we_i     : in  std_ulogic; -- write enable
      host_re_i     : in  std_ulogic; -- read enable
      host_cancel_i : in  std_ulogic; -- cancel current bus transaction
      host_lock_i   : in  std_ulogic; -- locked/exclusive access
      host_ack_o    : out std_ulogic; -- bus transfer acknowledge
      host_err_o    : out std_ulogic; -- bus transfer error
      -- peripheral bus interface --
      bus_addr_o    : out std_ulogic_vector(data_width_c-1 downto 0); -- bus access address
      bus_rdata_i   : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus read data
      bus_wdata_o   : out std_ulogic_vector(data_width_c-1 downto 0); -- bus write data
      bus_ben_o     : out std_ulogic_vector(03 downto 0); -- byte enable
      bus_we_o      : out std_ulogic; -- write enable
      bus_re_o      : out std_ulogic; -- read enable
      bus_cancel_o  : out std_ulogic; -- cancel current bus transaction
      bus_lock_o    : out std_ulogic; -- locked/exclusive access
      bus_ack_i     : in  std_ulogic; -- bus transfer acknowledge
      bus_err_i     : in  std_ulogic  -- bus transfer error
    );
  end component;
 
  -- Component: CPU Bus Switch --------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_busswitch
    generic (
      PORT_CA_READ_ONLY : boolean := false; -- set if controller port A is read-only
      PORT_CB_READ_ONLY : boolean := false  -- set if controller port B is read-only
    );
    port (
      -- global control --
      clk_i           : in  std_ulogic; -- global clock, rising edge
      rstn_i          : in  std_ulogic; -- global reset, low-active, async
      -- controller interface a --
      ca_bus_addr_i   : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus access address
      ca_bus_rdata_o  : out std_ulogic_vector(data_width_c-1 downto 0); -- bus read data
      ca_bus_wdata_i  : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus write data
      ca_bus_ben_i    : in  std_ulogic_vector(03 downto 0); -- byte enable
      ca_bus_we_i     : in  std_ulogic; -- write enable
      ca_bus_re_i     : in  std_ulogic; -- read enable
      ca_bus_cancel_i : in  std_ulogic; -- cancel current bus transaction
      ca_bus_lock_i   : in  std_ulogic; -- locked/exclusive access
      ca_bus_ack_o    : out std_ulogic; -- bus transfer acknowledge
      ca_bus_err_o    : out std_ulogic; -- bus transfer error
      -- controller interface b --
      cb_bus_addr_i   : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus access address
      cb_bus_rdata_o  : out std_ulogic_vector(data_width_c-1 downto 0); -- bus read data
      cb_bus_wdata_i  : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus write data
      cb_bus_ben_i    : in  std_ulogic_vector(03 downto 0); -- byte enable
      cb_bus_we_i     : in  std_ulogic; -- write enable
      cb_bus_re_i     : in  std_ulogic; -- read enable
      cb_bus_cancel_i : in  std_ulogic; -- cancel current bus transaction
      cb_bus_lock_i   : in  std_ulogic; -- locked/exclusive access
      cb_bus_ack_o    : out std_ulogic; -- bus transfer acknowledge
      cb_bus_err_o    : out std_ulogic; -- bus transfer error
      -- peripheral bus --
      p_bus_src_o     : out std_ulogic; -- access source: 0 = A, 1 = B
      p_bus_addr_o    : out std_ulogic_vector(data_width_c-1 downto 0); -- bus access address
      p_bus_rdata_i   : in  std_ulogic_vector(data_width_c-1 downto 0); -- bus read data
      p_bus_wdata_o   : out std_ulogic_vector(data_width_c-1 downto 0); -- bus write data
      p_bus_ben_o     : out std_ulogic_vector(03 downto 0); -- byte enable
      p_bus_we_o      : out std_ulogic; -- write enable
      p_bus_re_o      : out std_ulogic; -- read enable
      p_bus_cancel_o  : out std_ulogic; -- cancel current bus transaction
      p_bus_lock_o    : out std_ulogic; -- locked/exclusive access
      p_bus_ack_i     : in  std_ulogic; -- bus transfer acknowledge
      p_bus_err_i     : in  std_ulogic  -- bus transfer error
    );
  end component;
 
  -- Component: CPU Compressed Instructions Decompressor ------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_cpu_decompressor
    port (
      -- instruction input --
      ci_instr16_i : in  std_ulogic_vector(15 downto 0); -- compressed instruction input
      -- instruction output --
      ci_illegal_o : out std_ulogic; -- is an illegal compressed instruction
      ci_instr32_o : out std_ulogic_vector(31 downto 0)  -- 32-bit decompressed instruction
    );
  end component;
 
  -- Component: Processor-internal instruction memory (IMEM) --------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_imem
    generic (
      IMEM_BASE      : std_ulogic_vector(31 downto 0) := x"00000000"; -- memory base address
      IMEM_SIZE      : natural := 4*1024; -- processor-internal instruction memory size in bytes
      IMEM_AS_ROM    : boolean := false;  -- implement IMEM as read-only memory?
      BOOTLOADER_EN  : boolean := true    -- implement and use bootloader?
    );
    port (
      clk_i  : in  std_ulogic; -- global clock line
      rden_i : in  std_ulogic; -- read enable
      wren_i : in  std_ulogic; -- write enable
      ben_i  : in  std_ulogic_vector(03 downto 0); -- byte write enable
      addr_i : in  std_ulogic_vector(31 downto 0); -- address
      data_i : in  std_ulogic_vector(31 downto 0); -- data in
      data_o : out std_ulogic_vector(31 downto 0); -- data out
      ack_o  : out std_ulogic -- transfer acknowledge
    );
  end component;
 
  -- Component: Processor-internal data memory (DMEM) ---------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_dmem
    generic (
      DMEM_BASE : std_ulogic_vector(31 downto 0) := x"80000000"; -- memory base address
      DMEM_SIZE : natural := 4*1024  -- processor-internal instruction memory size in bytes
    );
    port (
      clk_i  : in  std_ulogic; -- global clock line
      rden_i : in  std_ulogic; -- read enable
      wren_i : in  std_ulogic; -- write enable
      ben_i  : in  std_ulogic_vector(03 downto 0); -- byte write enable
      addr_i : in  std_ulogic_vector(31 downto 0); -- address
      data_i : in  std_ulogic_vector(31 downto 0); -- data in
      data_o : out std_ulogic_vector(31 downto 0); -- data out
      ack_o  : out std_ulogic -- transfer acknowledge
    );
  end component;
 
  -- Component: Processor-internal bootloader ROM (BOOTROM) ---------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_boot_rom
    generic (
      BOOTROM_BASE : std_ulogic_vector(31 downto 0) := x"FFFF0000"; -- boot ROM base address
      BOOTROM_SIZE : natural := 4*1024  -- processor-internal boot ROM memory size in bytes
    );
    port (
      clk_i  : in  std_ulogic; -- global clock line
      rden_i : in  std_ulogic; -- read enable
      addr_i : in  std_ulogic_vector(31 downto 0); -- address
      data_o : out std_ulogic_vector(31 downto 0); -- data out
      ack_o  : out std_ulogic -- transfer acknowledge
    );
  end component;
 
  -- Component: Machine System Timer (mtime) ------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_mtime
    port (
      -- host access --
      clk_i     : in  std_ulogic; -- global clock line
      rstn_i    : in  std_ulogic := '0'; -- global reset, low-active, async
      addr_i    : in  std_ulogic_vector(31 downto 0); -- address
      rden_i    : in  std_ulogic; -- read enable
      wren_i    : in  std_ulogic; -- write enable
      data_i    : in  std_ulogic_vector(31 downto 0); -- data in
      data_o    : out std_ulogic_vector(31 downto 0); -- data out
      ack_o     : out std_ulogic; -- transfer acknowledge
      -- time output for CPU --
      time_o    : out std_ulogic_vector(63 downto 0); -- current system time
      -- interrupt --
      irq_o     : out std_ulogic  -- interrupt request
    );
  end component;
 
  -- Component: General Purpose Input/Output Port (GPIO) ------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_gpio
    port (
      -- host access --
      clk_i  : in  std_ulogic; -- global clock line
      addr_i : in  std_ulogic_vector(31 downto 0); -- address
      rden_i : in  std_ulogic; -- read enable
      wren_i : in  std_ulogic; -- write enable
      data_i : in  std_ulogic_vector(31 downto 0); -- data in
      data_o : out std_ulogic_vector(31 downto 0); -- data out
      ack_o  : out std_ulogic; -- transfer acknowledge
      -- parallel io --
      gpio_o : out std_ulogic_vector(31 downto 0);
      gpio_i : in  std_ulogic_vector(31 downto 0);
      -- interrupt --
      irq_o  : out std_ulogic
    );
  end component;
 
  -- Component: Watchdog Timer (WDT) --------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_wdt
    port (
      -- host access --
      clk_i       : in  std_ulogic; -- global clock line
      rstn_i      : in  std_ulogic; -- global reset line, low-active
      rden_i      : in  std_ulogic; -- read enable
      wren_i      : in  std_ulogic; -- write enable
      addr_i      : in  std_ulogic_vector(31 downto 0); -- address
      data_i      : in  std_ulogic_vector(31 downto 0); -- data in
      data_o      : out std_ulogic_vector(31 downto 0); -- data out
      ack_o       : out std_ulogic; -- transfer acknowledge
      -- clock generator --
      clkgen_en_o : out std_ulogic; -- enable clock generator
      clkgen_i    : in  std_ulogic_vector(07 downto 0);
      -- timeout event --
      irq_o       : out std_ulogic; -- timeout IRQ
      rstn_o      : out std_ulogic  -- timeout reset, low_active, use it as async!
    );
  end component;
 
  -- Component: Universal Asynchronous Receiver and Transmitter (UART) ----------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_uart
    port (
      -- host access --
      clk_i       : in  std_ulogic; -- global clock line
      addr_i      : in  std_ulogic_vector(31 downto 0); -- address
      rden_i      : in  std_ulogic; -- read enable
      wren_i      : in  std_ulogic; -- write enable
      data_i      : in  std_ulogic_vector(31 downto 0); -- data in
      data_o      : out std_ulogic_vector(31 downto 0); -- data out
      ack_o       : out std_ulogic; -- transfer acknowledge
      -- clock generator --
      clkgen_en_o : out std_ulogic; -- enable clock generator
      clkgen_i    : in  std_ulogic_vector(07 downto 0);
      -- com lines --
      uart_txd_o  : out std_ulogic;
      uart_rxd_i  : in  std_ulogic;
      -- interrupts --
      irq_rxd_o   : out std_ulogic; -- uart data received interrupt
      irq_txd_o   : out std_ulogic  -- uart transmission done interrupt
    );
  end component;
 
  -- Component: Serial Peripheral Interface (SPI) -------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_spi
    port (
      -- host access --
      clk_i       : in  std_ulogic; -- global clock line
      addr_i      : in  std_ulogic_vector(31 downto 0); -- address
      rden_i      : in  std_ulogic; -- read enable
      wren_i      : in  std_ulogic; -- write enable
      data_i      : in  std_ulogic_vector(31 downto 0); -- data in
      data_o      : out std_ulogic_vector(31 downto 0); -- data out
      ack_o       : out std_ulogic; -- transfer acknowledge
      -- clock generator --
      clkgen_en_o : out std_ulogic; -- enable clock generator
      clkgen_i    : in  std_ulogic_vector(07 downto 0);
      -- com lines --
      spi_sck_o   : out std_ulogic; -- SPI serial clock
      spi_sdo_o   : out std_ulogic; -- controller data out, peripheral data in
      spi_sdi_i   : in  std_ulogic; -- controller data in, peripheral data out
      spi_csn_o   : out std_ulogic_vector(07 downto 0); -- SPI CS
      -- interrupt --
      irq_o       : out std_ulogic -- transmission done interrupt
    );
  end component;
 
  -- Component: Two-Wire Interface (TWI) ----------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_twi
    port (
      -- host access --
      clk_i       : in  std_ulogic; -- global clock line
      addr_i      : in  std_ulogic_vector(31 downto 0); -- address
      rden_i      : in  std_ulogic; -- read enable
      wren_i      : in  std_ulogic; -- write enable
      data_i      : in  std_ulogic_vector(31 downto 0); -- data in
      data_o      : out std_ulogic_vector(31 downto 0); -- data out
      ack_o       : out std_ulogic; -- transfer acknowledge
      -- clock generator --
      clkgen_en_o : out std_ulogic; -- enable clock generator
      clkgen_i    : in  std_ulogic_vector(07 downto 0);
      -- com lines --
      twi_sda_io  : inout std_logic; -- serial data line
      twi_scl_io  : inout std_logic; -- serial clock line
      -- interrupt --
      irq_o       : out std_ulogic -- transfer done IRQ
    );
  end component;
 
  -- Component: Pulse-Width Modulation Controller (PWM) -------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_pwm
    port (
      -- host access --
      clk_i       : in  std_ulogic; -- global clock line
      addr_i      : in  std_ulogic_vector(31 downto 0); -- address
      rden_i      : in  std_ulogic; -- read enable
      wren_i      : in  std_ulogic; -- write enable
      data_i      : in  std_ulogic_vector(31 downto 0); -- data in
      data_o      : out std_ulogic_vector(31 downto 0); -- data out
      ack_o       : out std_ulogic; -- transfer acknowledge
      -- clock generator --
      clkgen_en_o : out std_ulogic; -- enable clock generator
      clkgen_i    : in  std_ulogic_vector(07 downto 0);
      -- pwm output channels --
      pwm_o       : out std_ulogic_vector(03 downto 0)
    );
  end component;
 
  -- Component: True Random Number Generator (TRNG) -----------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_trng
    port (
      -- host access --
      clk_i  : in  std_ulogic; -- global clock line
      addr_i : in  std_ulogic_vector(31 downto 0); -- address
      rden_i : in  std_ulogic; -- read enable
      wren_i : in  std_ulogic; -- write enable
      data_i : in  std_ulogic_vector(31 downto 0); -- data in
      data_o : out std_ulogic_vector(31 downto 0); -- data out
      ack_o  : out std_ulogic  -- transfer acknowledge
    );
  end component;
 
  -- Component: Wishbone Bus Gateway (WISHBONE) ---------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_wishbone
    generic (
      WB_PIPELINED_MODE : boolean := false; -- false: classic/standard wishbone mode, true: pipelined wishbone mode
      -- Internal instruction memory --
      MEM_INT_IMEM_EN   : boolean := true;   -- implement processor-internal instruction memory
      MEM_INT_IMEM_SIZE : natural := 8*1024; -- size of processor-internal instruction memory in bytes
      -- Internal data memory --
      MEM_INT_DMEM_EN   : boolean := true;   -- implement processor-internal data memory
      MEM_INT_DMEM_SIZE : natural := 4*1024  -- size of processor-internal data memory in bytes
    );
    port (
      -- global control --
      clk_i     : in  std_ulogic; -- global clock line
      rstn_i    : in  std_ulogic; -- global reset line, low-active
      -- host access --
      src_i     : in  std_ulogic; -- access type (0: data, 1:instruction)
      addr_i    : in  std_ulogic_vector(31 downto 0); -- address
      rden_i    : in  std_ulogic; -- read enable
      wren_i    : in  std_ulogic; -- write enable
      ben_i     : in  std_ulogic_vector(03 downto 0); -- byte write enable
      data_i    : in  std_ulogic_vector(31 downto 0); -- data in
      data_o    : out std_ulogic_vector(31 downto 0); -- data out
      cancel_i  : in  std_ulogic; -- cancel current bus transaction
      lock_i    : in  std_ulogic; -- locked/exclusive bus access
      ack_o     : out std_ulogic; -- transfer acknowledge
      err_o     : out std_ulogic; -- transfer error
      priv_i    : in  std_ulogic_vector(1 downto 0); -- current CPU privilege level
      -- wishbone interface --
      wb_tag_o  : out std_ulogic_vector(2 downto 0); -- tag
      wb_adr_o  : out std_ulogic_vector(31 downto 0); -- address
      wb_dat_i  : in  std_ulogic_vector(31 downto 0); -- read data
      wb_dat_o  : out std_ulogic_vector(31 downto 0); -- write data
      wb_we_o   : out std_ulogic; -- read/write
      wb_sel_o  : out std_ulogic_vector(03 downto 0); -- byte enable
      wb_stb_o  : out std_ulogic; -- strobe
      wb_cyc_o  : out std_ulogic; -- valid cycle
      wb_lock_o : out std_ulogic; -- locked/exclusive bus access
      wb_ack_i  : in  std_ulogic; -- transfer acknowledge
      wb_err_i  : in  std_ulogic  -- transfer error
    );
  end component;
 
  -- Component: Custom Functions Subsystem (CFS) --------------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_cfs
    generic (
      CFS_CONFIG : std_ulogic_vector(31 downto 0) := x"00000000" -- custom CFS configuration generic
    );
    port (
      -- host access --
      clk_i       : in  std_ulogic; -- global clock line
      rstn_i      : in  std_ulogic; -- global reset line, low-active, use as async
      addr_i      : in  std_ulogic_vector(31 downto 0); -- address
      rden_i      : in  std_ulogic; -- read enable
      wren_i      : in  std_ulogic; -- word write enable
      data_i      : in  std_ulogic_vector(31 downto 0); -- data in
      data_o      : out std_ulogic_vector(31 downto 0); -- data out
      ack_o       : out std_ulogic; -- transfer acknowledge
      err_o       : out std_ulogic; -- transfer error
      -- clock generator --
      clkgen_en_o : out std_ulogic; -- enable clock generator
      clkgen_i    : in  std_ulogic_vector(07 downto 0); -- "clock" inputs
      -- CPU state --
      sleep_i     : in  std_ulogic; -- set if cpu is in sleep mode
      -- interrupt --
      irq_o       : out std_ulogic; -- interrupt request
      irq_ack_i   : in  std_ulogic; -- interrupt acknowledge
      -- custom io (conduit) --
      cfs_in_i    : in  std_ulogic_vector(31 downto 0); -- custom inputs
      cfs_out_o   : out std_ulogic_vector(31 downto 0)  -- custom outputs
    );
  end component;
 
  -- Component: Numerically-Controlled Oscillator (NCO) -------------------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_nco
    port (
      -- host access --
      clk_i       : in  std_ulogic; -- global clock line
      addr_i      : in  std_ulogic_vector(31 downto 0); -- address
      rden_i      : in  std_ulogic; -- read enable
      wren_i      : in  std_ulogic; -- write enable
      data_i      : in  std_ulogic_vector(31 downto 0); -- data in
      data_o      : out std_ulogic_vector(31 downto 0); -- data out
      ack_o       : out std_ulogic; -- transfer acknowledge
      -- clock generator --
      clkgen_en_o : out std_ulogic; -- enable clock generator
      clkgen_i    : in  std_ulogic_vector(07 downto 0);
      -- NCO output --
      nco_o       : out std_ulogic_vector(02 downto 0)
    );
  end component;
 
  -- Component: System Configuration Information Memory (SYSINFO) ---------------------------
  -- -------------------------------------------------------------------------------------------
  component neorv32_sysinfo
    generic (
      -- General --
      CLOCK_FREQUENCY      : natural := 0;      -- clock frequency of clk_i in Hz
      BOOTLOADER_EN        : boolean := true;   -- implement processor-internal bootloader?
      USER_CODE            : std_ulogic_vector(31 downto 0) := x"00000000"; -- custom user code
      -- Internal Instruction memory --
      MEM_INT_IMEM_EN      : boolean := true;   -- implement processor-internal instruction memory
      MEM_INT_IMEM_SIZE    : natural := 8*1024; -- size of processor-internal instruction memory in bytes
      MEM_INT_IMEM_ROM     : boolean := false;  -- implement processor-internal instruction memory as ROM
      -- Internal Data memory --
      MEM_INT_DMEM_EN      : boolean := true;   -- implement processor-internal data memory
      MEM_INT_DMEM_SIZE    : natural := 4*1024; -- size of processor-internal data memory in bytes
      -- Internal Cache memory --
      ICACHE_EN            : boolean := true;   -- implement instruction cache
      ICACHE_NUM_BLOCKS    : natural := 4;      -- i-cache: number of blocks (min 2), has to be a power of 2
      ICACHE_BLOCK_SIZE    : natural := 64;     -- i-cache: block size in bytes (min 4), has to be a power of 2
      ICACHE_ASSOCIATIVITY : natural := 1;      -- i-cache: associativity (min 1), has to be a power 2
      -- External memory interface --
      MEM_EXT_EN           : boolean := false;  -- implement external memory bus interface?
      -- Processor peripherals --
      IO_GPIO_EN           : boolean := true;   -- implement general purpose input/output port unit (GPIO)?
      IO_MTIME_EN          : boolean := true;   -- implement machine system timer (MTIME)?
      IO_UART_EN           : boolean := true;   -- implement universal asynchronous receiver/transmitter (UART)?
      IO_SPI_EN            : boolean := true;   -- implement serial peripheral interface (SPI)?
      IO_TWI_EN            : boolean := true;   -- implement two-wire interface (TWI)?
      IO_PWM_EN            : boolean := true;   -- implement pulse-width modulation unit (PWM)?
      IO_WDT_EN            : boolean := true;   -- implement watch dog timer (WDT)?
      IO_TRNG_EN           : boolean := true;   -- implement true random number generator (TRNG)?
      IO_CFS_EN            : boolean := true;   -- implement custom functions subsystem (CFS)?
      IO_NCO_EN            : boolean := true    -- implement numerically-controlled oscillator (NCO)?
    );
    port (
      -- host access --
      clk_i  : in  std_ulogic; -- global clock line
      addr_i : in  std_ulogic_vector(31 downto 0); -- address
      rden_i : in  std_ulogic; -- read enable
      data_o : out std_ulogic_vector(31 downto 0); -- data out
      ack_o  : out std_ulogic  -- transfer acknowledge
    );
  end component;
 
end neorv32_package;
 
package body neorv32_package is
 
  -- Function: Minimal required number of bits to represent input number --------------------
  -- -------------------------------------------------------------------------------------------
  function index_size_f(input : natural) return natural is
  begin
    for i in 0 to natural'high loop
      if (2**i >= input) then
        return i;
      end if;
    end loop; -- i
    return 0;
  end function index_size_f;
 
  -- Function: Conditional select natural ---------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  function cond_sel_natural_f(cond : boolean; val_t : natural; val_f : natural) return natural is
  begin
    if (cond = true) then
      return val_t;
    else
      return val_f;
    end if;
  end function cond_sel_natural_f;
 
  -- Function: Conditional select std_ulogic_vector -----------------------------------------
  -- -------------------------------------------------------------------------------------------
  function cond_sel_stdulogicvector_f(cond : boolean; val_t : std_ulogic_vector; val_f : std_ulogic_vector) return std_ulogic_vector is
  begin
    if (cond = true) then
      return val_t;
    else
      return val_f;
    end if;
  end function cond_sel_stdulogicvector_f;
 
  -- Function: Convert BOOL to STD_ULOGIC ---------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  function bool_to_ulogic_f(cond : boolean) return std_ulogic is
  begin
    if (cond = true) then
      return '1';
    else
      return '0';
    end if;
  end function bool_to_ulogic_f;
 
  -- Function: OR all bits ------------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  function or_all_f(a : std_ulogic_vector) return std_ulogic is
    variable tmp_v : std_ulogic;
  begin
    tmp_v := a(a'low);
    if (a'low < a'high) then -- not null range?
      for i in a'low+1 to a'high loop
        tmp_v := tmp_v or a(i);
      end loop; -- i
    end if;
    return tmp_v;
  end function or_all_f;
 
  -- Function: AND all bits -----------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  function and_all_f(a : std_ulogic_vector) return std_ulogic is
    variable tmp_v : std_ulogic;
  begin
    tmp_v := a(a'low);
    if (a'low < a'high) then -- not null range?
      for i in a'low+1 to a'high loop
        tmp_v := tmp_v and a(i);
      end loop; -- i
    end if;
    return tmp_v;
  end function and_all_f;
 
  -- Function: XOR all bits -----------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  function xor_all_f(a : std_ulogic_vector) return std_ulogic is
    variable tmp_v : std_ulogic;
  begin
    tmp_v := a(a'low);
    if (a'low < a'high) then -- not null range?
      for i in a'low+1 to a'high loop
        tmp_v := tmp_v xor a(i);
      end loop; -- i
    end if;
    return tmp_v;
  end function xor_all_f;
 
  -- Function: XNOR all bits ----------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  function xnor_all_f(a : std_ulogic_vector) return std_ulogic is
    variable tmp_v : std_ulogic;
  begin
    tmp_v := a(a'low);
    if (a'low < a'high) then -- not null range?
      for i in a'low+1 to a'high loop
        tmp_v := tmp_v xnor a(i);
      end loop; -- i
    end if;
    return tmp_v;
  end function xnor_all_f;
 
  -- Function: Convert std_ulogic_vector to hex char ----------------------------------------
  -- -------------------------------------------------------------------------------------------
  function to_hexchar_f(input : std_ulogic_vector(3 downto 0)) return character is
    variable output_v : character;
  begin
    case input is
      when x"0"   => output_v := '0';
      when x"1"   => output_v := '1';
      when x"2"   => output_v := '2';
      when x"3"   => output_v := '3';
      when x"4"   => output_v := '4';
      when x"5"   => output_v := '5';
      when x"6"   => output_v := '6';
      when x"7"   => output_v := '7';
      when x"8"   => output_v := '8';
      when x"9"   => output_v := '9';
      when x"a"   => output_v := 'a';
      when x"b"   => output_v := 'b';
      when x"c"   => output_v := 'c';
      when x"d"   => output_v := 'd';
      when x"e"   => output_v := 'e';
      when x"f"   => output_v := 'f';
      when others => output_v := '?';
    end case;
    return output_v;
  end function to_hexchar_f;
 
  -- Function: Convert hex char to std_ulogic_vector ----------------------------------------
  -- -------------------------------------------------------------------------------------------
  function hexchar_to_stdulogicvector_f(input : character) return std_ulogic_vector is
    variable hex_value_v : std_ulogic_vector(3 downto 0);
  begin
    case input is
      when '0'       => hex_value_v := x"0";
      when '1'       => hex_value_v := x"1";
      when '2'       => hex_value_v := x"2";
      when '3'       => hex_value_v := x"3"; 
      when '4'       => hex_value_v := x"4";
      when '5'       => hex_value_v := x"5";
      when '6'       => hex_value_v := x"6";
      when '7'       => hex_value_v := x"7";
      when '8'       => hex_value_v := x"8";
      when '9'       => hex_value_v := x"9";
      when 'a' | 'A' => hex_value_v := x"a";
      when 'b' | 'B' => hex_value_v := x"b";
      when 'c' | 'C' => hex_value_v := x"c";
      when 'd' | 'D' => hex_value_v := x"d";
      when 'e' | 'E' => hex_value_v := x"e";
      when 'f' | 'F' => hex_value_v := x"f";
      when others    => hex_value_v := (others => 'X');
    end case;
    return hex_value_v;
  end function hexchar_to_stdulogicvector_f;
 
  -- Function: Bit reversal -----------------------------------------------------------------
  -- -------------------------------------------------------------------------------------------
  function bit_rev_f(input : std_ulogic_vector) return std_ulogic_vector is
    variable output_v : std_ulogic_vector(input'range);
  begin
    for i in 0 to input'length-1 loop
      output_v(input'length-i-1) := input(i);
    end loop; -- i
    return output_v;
  end function bit_rev_f;
 
  -- Function: Test if input number is a power of two ---------------------------------------
  -- -------------------------------------------------------------------------------------------
  function is_power_of_two_f(input : natural) return boolean is
  begin
    if (input = 1) then -- 2^0
      return true;
    elsif ((input / 2) /= 0) and ((input mod 2) = 0) then
      return true;
    else
      return false;
    end if;
  end function is_power_of_two_f;
 
  -- Function: Swap all bytes of a 32-bit word (endianness conversion) ----------------------
  -- -------------------------------------------------------------------------------------------
  function bswap32_f(input : std_ulogic_vector) return std_ulogic_vector is
    variable output_v : std_ulogic_vector(input'range);
  begin
    output_v(07 downto 00) := input(31 downto 24);
    output_v(15 downto 08) := input(23 downto 16);
    output_v(23 downto 16) := input(15 downto 08);
    output_v(31 downto 24) := input(07 downto 00);
    return output_v;
  end function bswap32_f;
 
end neorv32_package;
 

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