Subversion Repositories neorv32

-- #################################################################################################

-- # << NEORV32 - CPU Top Entity >>                                                                #

-- # ********************************************************************************************* #

-- # Top NEORV32 CPU:                                                                              #

-- # * neorv32_cpu_alu: Arithemtical/logical unit                                                  #

-- # * neorv32_cpu_ctrl: CPU control and CSR system                                                #

-- #   * neorv32_cpu_decompressor: Compressed instructions decoder                                 #

-- # * neorv32_cpu_bus: Memory/IO bus interface unit                                               #

-- # * neorv32_cpu_cp_muldiv: MULDIV co-processor                                                  #

-- # * neorv32_cpu_regfile: Data register file                                                     #

-- # ********************************************************************************************* #

-- # BSD 3-Clause License                                                                          #

-- #                                                                                               #

-- # Copyright (c) 2020, 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;

library neorv32;

use neorv32.neorv32_package.all;

entity neorv32_cpu is

  generic (

    -- General --

    CLOCK_FREQUENCY              : natural := 0; -- clock frequency of clk_i in Hz

    HART_ID                      : std_ulogic_vector(31 downto 0) := x"00000000"; -- custom hardware thread ID

    BOOTLOADER_USE               : boolean := true;   -- implement processor-internal bootloader?

    CSR_COUNTERS_USE             : boolean := true;   -- implement RISC-V perf. counters ([m]instret[h], [m]cycle[h], time[h])?

    -- RISC-V CPU 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_Zicsr    : boolean := true;   -- implement CSR system?

    CPU_EXTENSION_RISCV_Zifencei : boolean := true;   -- implement instruction stream sync.?

    -- Memory configuration: Instruction memory --

    MEM_ISPACE_BASE              : std_ulogic_vector(31 downto 0) := x"00000000"; -- base address of instruction memory space

    MEM_ISPACE_SIZE              : natural := 8*1024; -- total size of instruction memory space in byte

    MEM_INT_IMEM_USE             : 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

    -- Memory configuration: Data memory --

    MEM_DSPACE_BASE              : std_ulogic_vector(31 downto 0) := x"80000000"; -- base address of data memory space

    MEM_DSPACE_SIZE              : natural := 4*1024; -- total size of data memory space in byte

    MEM_INT_DMEM_USE             : boolean := true;   -- implement processor-internal data memory

    MEM_INT_DMEM_SIZE            : natural := 4*1024; -- size of processor-internal data memory in bytes

    -- Memory configuration: External memory interface --

    MEM_EXT_USE                  : boolean := false;  -- implement external memory bus interface?

    MEM_EXT_TIMEOUT              : natural := 15;     -- cycles after which a valid bus access will timeout

    -- Processor peripherals --

    IO_GPIO_USE                  : boolean := true;   -- implement general purpose input/output port unit (GPIO)?

    IO_MTIME_USE                 : boolean := true;   -- implement machine system timer (MTIME)?

    IO_UART_USE                  : boolean := true;   -- implement universal asynchronous receiver/transmitter (UART)?

    IO_SPI_USE                   : boolean := true;   -- implement serial peripheral interface (SPI)?

    IO_TWI_USE                   : boolean := true;   -- implement two-wire interface (TWI)?

    IO_PWM_USE                   : boolean := true;   -- implement pulse-width modulation unit (PWM)?

    IO_WDT_USE                   : boolean := true;   -- implement watch dog timer (WDT)?

    IO_CLIC_USE                  : boolean := true;   -- implement core local interrupt controller (CLIC)?

    IO_TRNG_USE                  : boolean := true;   -- implement true random number generator (TRNG)?

    IO_DEVNULL_USE               : boolean := true    -- implement dummy device (DEVNULL)?

  );

  port (

    -- global control --

    clk_i       : in  std_ulogic; -- global clock, rising edge

    rstn_i      : in  std_ulogic; -- global reset, low-active, async

    -- 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_ack_i   : in  std_ulogic; -- bus transfer acknowledge

    bus_err_i   : in  std_ulogic; -- bus transfer error

    -- external interrupts --

    clic_irq_i  : in  std_ulogic; -- CLIC interrupt request

    mtime_irq_i : in  std_ulogic  -- machine timer interrupt

  );

end neorv32_cpu;

architecture neorv32_cpu_rtl of neorv32_cpu is

  -- local signals --

  signal ctrl        : std_ulogic_vector(ctrl_width_c-1 downto 0); -- main control bus

  signal alu_cmp     : std_ulogic_vector(1 downto 0); -- alu comparator result

  signal imm         : std_ulogic_vector(data_width_c-1 downto 0); -- immediate

  signal instr       : std_ulogic_vector(data_width_c-1 downto 0); -- new instruction

  signal rs1, rs2    : std_ulogic_vector(data_width_c-1 downto 0); -- source registers

  signal alu_res     : std_ulogic_vector(data_width_c-1 downto 0); -- alu result

  signal alu_add     : std_ulogic_vector(data_width_c-1 downto 0); -- alu adder result

  signal rdata       : std_ulogic_vector(data_width_c-1 downto 0); -- memory read data

  signal alu_wait    : std_ulogic; -- alu is busy due to iterative unit

  signal bus_wait    : std_ulogic; -- wait for bus to finish operation

  signal csr_rdata   : std_ulogic_vector(data_width_c-1 downto 0); -- csr read data

  signal mar         : std_ulogic_vector(data_width_c-1 downto 0); -- current memory address register

  signal ma_instr    : std_ulogic; -- misaligned instruction address

  signal ma_load     : std_ulogic; -- misaligned load data address

  signal ma_store    : std_ulogic; -- misaligned store data address

  signal be_instr    : std_ulogic; -- bus error on instruction access

  signal be_load     : std_ulogic; -- bus error on load data access

  signal be_store    : std_ulogic; -- bus error on store data access

  signal bus_exc_ack : std_ulogic; -- bus exception error acknowledge

  signal bus_busy    : std_ulogic; -- bus unit is busy

  signal fetch_pc    : std_ulogic_vector(data_width_c-1 downto 0); -- pc for instruction fetch

  signal curr_pc     : std_ulogic_vector(data_width_c-1 downto 0); -- current pc (for current executed instruction)

  signal next_pc     : std_ulogic_vector(data_width_c-1 downto 0); -- next pc (for current executed instruction)

  -- co-processor interface --

  signal cp0_data,  cp1_data  : std_ulogic_vector(data_width_c-1 downto 0);

  signal cp0_valid, cp1_valid : std_ulogic;

begin

  -- Control Unit ---------------------------------------------------------------------------

  -- -------------------------------------------------------------------------------------------

  neorv32_cpu_control_inst: neorv32_cpu_control

  generic map (

    -- General --

    CLOCK_FREQUENCY              => CLOCK_FREQUENCY,  -- clock frequency of clk_i in Hz

    HART_ID                      => HART_ID,          -- custom hardware thread ID

    BOOTLOADER_USE               => BOOTLOADER_USE,   -- implement processor-internal bootloader?

    CSR_COUNTERS_USE             => CSR_COUNTERS_USE, -- implement RISC-V perf. counters ([m]instret[h], [m]cycle[h], time[h])?

    -- RISC-V CPU Extensions --

    CPU_EXTENSION_RISCV_C        => CPU_EXTENSION_RISCV_C,     -- implement compressed extension?

    CPU_EXTENSION_RISCV_E        => CPU_EXTENSION_RISCV_E,     -- implement embedded RF extension?

    CPU_EXTENSION_RISCV_M        => CPU_EXTENSION_RISCV_M,     -- implement muld/div extension?

    CPU_EXTENSION_RISCV_Zicsr    => CPU_EXTENSION_RISCV_Zicsr, -- implement CSR system?

    CPU_EXTENSION_RISCV_Zifencei => CPU_EXTENSION_RISCV_Zifencei, -- implement instruction stream sync.?

    -- Memory configuration: Instruction memory --

    MEM_ISPACE_BASE              => MEM_ISPACE_BASE,   -- base address of instruction memory space

    MEM_ISPACE_SIZE              => MEM_ISPACE_SIZE,   -- total size of instruction memory space in byte

    MEM_INT_IMEM_USE             => MEM_INT_IMEM_USE,  -- implement processor-internal instruction memory

    MEM_INT_IMEM_SIZE            => MEM_INT_IMEM_SIZE, -- size of processor-internal instruction memory in bytes

    MEM_INT_IMEM_ROM             => MEM_INT_IMEM_ROM,  -- implement processor-internal instruction memory as ROM

    -- Memory configuration: Data memory --

    MEM_DSPACE_BASE              => MEM_DSPACE_BASE,   -- base address of data memory space

    MEM_DSPACE_SIZE              => MEM_DSPACE_SIZE,   -- total size of data memory space in byte

    MEM_INT_DMEM_USE             => MEM_INT_DMEM_USE,  -- implement processor-internal data memory

    MEM_INT_DMEM_SIZE            => MEM_INT_DMEM_SIZE, -- size of processor-internal data memory in bytes

    -- Memory configuration: External memory interface --

    MEM_EXT_USE                  => MEM_EXT_USE,       -- implement external memory bus interface?

    -- Processor peripherals --

    IO_GPIO_USE                  => IO_GPIO_USE,       -- implement general purpose input/output port unit (GPIO)?

    IO_MTIME_USE                 => IO_MTIME_USE,      -- implement machine system timer (MTIME)?

    IO_UART_USE                  => IO_UART_USE,       -- implement universal asynchronous receiver/transmitter (UART)?

    IO_SPI_USE                   => IO_SPI_USE,        -- implement serial peripheral interface (SPI)?

    IO_TWI_USE                   => IO_TWI_USE,        -- implement two-wire interface (TWI)?

    IO_PWM_USE                   => IO_PWM_USE,        -- implement pulse-width modulation unit (PWM)?

    IO_WDT_USE                   => IO_WDT_USE,        -- implement watch dog timer (WDT)?

    IO_CLIC_USE                  => IO_CLIC_USE,       -- implement core local interrupt controller (CLIC)?

    IO_TRNG_USE                  => IO_TRNG_USE,       -- implement true random number generator (TRNG)?

    IO_DEVNULL_USE               => IO_DEVNULL_USE     -- implement dummy device (DEVNULL)?

  )

  port map (

    -- global control --

    clk_i         => clk_i,       -- global clock, rising edge

    rstn_i        => rstn_i,      -- global reset, low-active, async

    ctrl_o        => ctrl,        -- main control bus

    -- status input --

    alu_wait_i    => alu_wait,    -- wait for ALU

    bus_wait_i    => bus_wait,    -- wait for bus

    -- data input --

    instr_i       => instr,       -- instruction

    cmp_i         => alu_cmp,     -- comparator status

    alu_add_i     => alu_add,     -- ALU.add result

    -- data output --

    imm_o         => imm,         -- immediate

    fetch_pc_o    => fetch_pc,    -- PC for instruction fetch

    curr_pc_o     => curr_pc,     -- current PC (corresponding to current instruction)

    next_pc_o     => next_pc,     -- next PC (corresponding to current instruction)

    -- csr interface --

    csr_wdata_i   => alu_res,     -- CSR write data

    csr_rdata_o   => csr_rdata,   -- CSR read data

    -- external interrupt --

    clic_irq_i    => clic_irq_i,  -- CLIC interrupt request

    mtime_irq_i   => mtime_irq_i, -- machine timer interrupt

    -- bus access exceptions --

    mar_i         => mar,         -- memory address register

    ma_instr_i    => ma_instr,    -- misaligned instruction address

    ma_load_i     => ma_load,     -- misaligned load data address

    ma_store_i    => ma_store,    -- misaligned store data address

    be_instr_i    => be_instr,    -- bus error on instruction access

    be_load_i     => be_load,     -- bus error on load data access

    be_store_i    => be_store,    -- bus error on store data access

    bus_exc_ack_o => bus_exc_ack, -- bus exception error acknowledge

    bus_busy_i    => bus_busy     -- bus unit is busy

  );

  -- Register File --------------------------------------------------------------------------

  -- -------------------------------------------------------------------------------------------

  neorv32_regfile_inst: neorv32_cpu_regfile

  generic map (

    CPU_EXTENSION_RISCV_E => CPU_EXTENSION_RISCV_E -- implement embedded RF extension?

  )

  port map (

    -- global control --

    clk_i  => clk_i,              -- global clock, rising edge

    ctrl_i => ctrl,               -- main control bus

    -- data input --

    mem_i  => rdata,              -- memory read data

    alu_i  => alu_res,            -- ALU result

    csr_i  => csr_rdata,          -- CSR read data

    pc_i   => next_pc,            -- next pc

    -- data output --

    rs1_o  => rs1,                -- operand 1

    rs2_o  => rs2                 -- operand 2

  );

  -- ALU ------------------------------------------------------------------------------------

  -- -------------------------------------------------------------------------------------------

  neorv32_cpu_alu_inst: neorv32_cpu_alu

  port map (

    -- global control --

    clk_i       => clk_i,         -- global clock, rising edge

    rstn_i      => rstn_i,        -- global reset, low-active, async

    ctrl_i      => ctrl,          -- main control bus

    -- data input --

    rs1_i       => rs1,           -- rf source 1

    rs2_i       => rs2,           -- rf source 2

    pc2_i       => curr_pc,       -- delayed PC

    imm_i       => imm,           -- immediate

    csr_i       => csr_rdata,     -- csr read data

    -- data output --

    cmp_o       => alu_cmp,       -- comparator status

    add_o       => alu_add,       -- OPA + OPB

    res_o       => alu_res,       -- ALU result

    -- co-processor interface --

    cp0_data_i  => cp0_data,      -- co-processor 0 result

    cp0_valid_i => cp0_valid,     -- co-processor 0 result valid

    cp1_data_i  => cp1_data,      -- co-processor 1 result

    cp1_valid_i => cp1_valid,     -- co-processor 1 result valid

    -- status --

    wait_o      => alu_wait       -- busy due to iterative processing units

  );

  -- Co-Processor 0: MULDIV Unit ------------------------------------------------------------

  -- -------------------------------------------------------------------------------------------

  neorv32_cpu_cp_muldiv_inst_true:

  if (CPU_EXTENSION_RISCV_M = true) generate

    neorv32_cpu_cp_muldiv_inst: neorv32_cpu_cp_muldiv

    port map (

      -- global control --

      clk_i   => clk_i,           -- global clock, rising edge

      rstn_i  => rstn_i,          -- global reset, low-active, async

      ctrl_i  => ctrl,            -- main control bus

      -- data input --

      rs1_i   => rs1,             -- rf source 1

      rs2_i   => rs2,             -- rf source 2

      -- result and status --

      res_o   => cp0_data,        -- operation result

      valid_o => cp0_valid        -- data output valid

    );

  end generate;

  neorv32_cpu_cp_muldiv_inst_false:

  if (CPU_EXTENSION_RISCV_M = false) generate

    cp0_data  <= (others => '0');

    cp0_valid <= '0';

  end generate;

  -- Co-Processor 1: Not Implemented Yet ----------------------------------------------------

  -- -------------------------------------------------------------------------------------------

  cp1_data  <= (others => '0');

  cp1_valid <= '0';

  -- Bus Unit -------------------------------------------------------------------------------

  -- -------------------------------------------------------------------------------------------

  neorv32_cpu_bus_inst: neorv32_cpu_bus

  generic map (

    MEM_EXT_TIMEOUT => MEM_EXT_TIMEOUT -- cycles after which a valid bus access will timeout

  )

  port map (

    -- global control --

    clk_i       => clk_i,         -- global clock, rising edge

    rstn_i      => rstn_i,        -- global reset, low-active, async

    ctrl_i      => ctrl,          -- main control bus

    -- data input --

    wdata_i     => rs2,           -- write data

    pc_i        => fetch_pc,      -- current PC for instruction fetch

    alu_i       => alu_res,       -- ALU result

    -- data output --

    instr_o     => instr,         -- instruction

    rdata_o     => rdata,         -- read data

    -- status --

    mar_o       => mar,           -- current memory address register

    ma_instr_o  => ma_instr,      -- misaligned instruction address

    ma_load_o   => ma_load,       -- misaligned load data address

    ma_store_o  => ma_store,      -- misaligned store data address

    be_instr_o  => be_instr,      -- bus error on instruction access

    be_load_o   => be_load,       -- bus error on load data access

    be_store_o  => be_store,      -- bus error on store data access

    bus_wait_o  => bus_wait,      -- wait for bus operation to finish

    bus_busy_o  => bus_busy,      -- bus unit is busy

    exc_ack_i   => bus_exc_ack,   -- exception controller ACK

    -- bus system --

    bus_addr_o  => bus_addr_o,    -- bus access address

    bus_rdata_i => bus_rdata_i,   -- bus read data

    bus_wdata_o => bus_wdata_o,   -- bus write data

    bus_ben_o   => bus_ben_o,     -- byte enable

    bus_we_o    => bus_we_o,      -- write enable

    bus_re_o    => bus_re_o,      -- read enable

    bus_ack_i   => bus_ack_i,     -- bus transfer acknowledge

    bus_err_i   => bus_err_i      -- bus transfer error

  );

end neorv32_cpu_rtl;