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-- signals in the ALU and PC records.
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-- signals in the ALU and PC records.
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-- Seth Henry 03/17/20 Added new subtype and constants for external
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-- Seth Henry 03/17/20 Added new subtype and constants for external
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-- GP flags.
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-- GP flags.
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-- Seth Henry 03/18/20 Added the ceil_log2 function, since it is used in
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-- Seth Henry 03/18/20 Added the ceil_log2 function, since it is used in
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-- memory sizing calculations.
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-- memory sizing calculations.
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-- Seth Henry 04/09/20 Added the I bit to the exported flags for use in
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-- memory protection schemes.
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library ieee;
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_arith.all;
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use ieee.std_logic_arith.all;
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subtype ADDRESS_TYPE is std_logic_vector(OPEN8_ADDR_WIDTH - 1 downto 0);
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subtype ADDRESS_TYPE is std_logic_vector(OPEN8_ADDR_WIDTH - 1 downto 0);
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subtype DATA_TYPE is std_logic_vector(OPEN8_DATA_WIDTH - 1 downto 0);
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subtype DATA_TYPE is std_logic_vector(OPEN8_DATA_WIDTH - 1 downto 0);
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-- Note: INTERRUPT_BUNDLE must be exactly the same width as DATA_TYPE
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-- Note: INTERRUPT_BUNDLE must be exactly the same width as DATA_TYPE
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subtype INTERRUPT_BUNDLE is DATA_TYPE;
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subtype INTERRUPT_BUNDLE is DATA_TYPE;
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subtype EXT_GP_FLAGS is std_logic_vector(3 downto 0);
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subtype EXT_GP_FLAGS is std_logic_vector(4 downto 0);
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constant EXT_GP4 : integer := 0;
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constant EXT_ISR : integer := 0;
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constant EXT_GP5 : integer := 1;
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constant EXT_GP4 : integer := 1;
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constant EXT_GP6 : integer := 2;
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constant EXT_GP5 : integer := 2;
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constant EXT_GP7 : integer := 3;
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constant EXT_GP6 : integer := 3;
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constant EXT_GP7 : integer := 4;
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constant OPEN8_NULLBUS : DATA_TYPE := x"00";
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constant OPEN8_NULLBUS : DATA_TYPE := x"00";
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-- Component declaration
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-- Component declaration
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-- (assumes a 1K RAM at 0x0000 and ROM at the top of the memory map)
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-- (assumes a 1K RAM at 0x0000 and ROM at the top of the memory map)
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