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library neorv32;
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library neorv32;
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use neorv32.neorv32_package.all;
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use neorv32.neorv32_package.all;
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use neorv32.neorv32_bootloader_image.all; -- this file is generated by the image generator
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use neorv32.neorv32_bootloader_image.all; -- this file is generated by the image generator
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entity neorv32_boot_rom is
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entity neorv32_boot_rom is
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generic (
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BOOTROM_BASE : std_ulogic_vector(31 downto 0) := x"FFFF0000"; -- boot ROM base address
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BOOTROM_SIZE : natural := 4*1024 -- processor-internal boot ROM memory size in bytes
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);
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port (
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port (
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clk_i : in std_ulogic; -- global clock line
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clk_i : in std_ulogic; -- global clock line
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rden_i : in std_ulogic; -- read enable
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rden_i : in std_ulogic; -- read enable
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addr_i : in std_ulogic_vector(31 downto 0); -- address
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addr_i : in std_ulogic_vector(31 downto 0); -- address
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data_o : out std_ulogic_vector(31 downto 0); -- data out
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data_o : out std_ulogic_vector(31 downto 0); -- data out
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end neorv32_boot_rom;
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end neorv32_boot_rom;
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architecture neorv32_boot_rom_rtl of neorv32_boot_rom is
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architecture neorv32_boot_rom_rtl of neorv32_boot_rom is
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-- local types --
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-- local types --
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type boot_img_t is array (0 to boot_size_c/4-1) of std_ulogic_vector(31 downto 0);
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type boot_img_t is array (0 to BOOTROM_SIZE/4-1) of std_ulogic_vector(31 downto 0);
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-- init function --
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-- init function --
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-- impure function: returns NOT the same result every time it is evaluated with the same arguments since the source file might have changed
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-- impure function: returns NOT the same result every time it is evaluated with the same arguments since the source file might have changed
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impure function init_boot_rom(init : bootloader_init_image_t) return boot_img_t is
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impure function init_boot_rom(init : bootloader_init_image_t) return boot_img_t is
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variable mem_v : boot_img_t;
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variable mem_v : boot_img_t;
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-- local signals --
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-- local signals --
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signal acc_en : std_ulogic;
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signal acc_en : std_ulogic;
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signal rden : std_ulogic;
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signal rden : std_ulogic;
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signal rdata : std_ulogic_vector(31 downto 0);
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signal rdata : std_ulogic_vector(31 downto 0);
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signal addr : std_ulogic_vector(index_size_f(boot_size_c/4)-1 downto 0);
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signal addr : std_ulogic_vector(index_size_f(BOOTROM_SIZE/4)-1 downto 0);
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-- bootloader image --
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-- bootloader image --
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constant boot_img : boot_img_t := init_boot_rom(bootloader_init_image);
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constant boot_img : boot_img_t := init_boot_rom(bootloader_init_image);
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begin
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begin
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-- Access Control -------------------------------------------------------------------------
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-- Access Control -------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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acc_en <= '1' when (addr_i >= boot_base_c) and (addr_i < std_ulogic_vector(unsigned(boot_base_c) + boot_size_c)) else '0';
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acc_en <= '1' when (addr_i >= BOOTROM_BASE) and (addr_i < std_ulogic_vector(unsigned(BOOTROM_BASE) + BOOTROM_SIZE)) else '0';
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addr <= addr_i(index_size_f(boot_size_c/4)+1 downto 2); -- word aligned
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addr <= addr_i(index_size_f(BOOTROM_SIZE/4)+1 downto 2); -- word aligned
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-- Memory Access --------------------------------------------------------------------------
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-- Memory Access --------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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mem_file_access: process(clk_i)
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mem_file_access: process(clk_i)
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