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[/] [open8_urisc/] [trunk/] [VHDL/] [Open8_cfg.vhd] - Blame information for rev 279

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-- VHDL Units :  Open8_cfg
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-- Description:  Contains an example Open8_cfg file
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--
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-- Revision History
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-- Author          Date     Change
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------------------ -------- ---------------------------------------------------
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-- Seth Henry      10/21/20 Design Start
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library ieee;
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  use ieee.std_logic_1164.all;
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  use ieee.std_logic_unsigned.all;
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  use ieee.std_logic_arith.all;
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library work;
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  use work.open8_pkg.all;
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package open8_cfg is
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  -- Internal Clock Frequency
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  constant Clock_Frequency          : real      := 120000000.0;
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    -- Open8 CPU Options
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  constant Allow_Stack_Address_Move : boolean   := TRUE;
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  constant Enable_Auto_Increment    : boolean   := TRUE;
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  constant BRK_Implements_WAI       : boolean   := TRUE;
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  constant Enable_NMI               : boolean   := TRUE;
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  constant Sequential_Interrupts    : boolean   := TRUE;
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  constant RTI_Ignores_GP_Flags     : boolean   := TRUE;
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  constant Supervisor_Mode          : boolean   := TRUE;
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  constant Unsigned_Index_Offsets   : boolean   := TRUE;
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  constant Default_Int_Mask         : DATA_TYPE := x"00";
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  -- System Memory Map
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  constant RAM_Address              : ADDRESS_TYPE := x"0000";  -- System RAM
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  constant WPR_Address              : ADDRESS_TYPE := x"1000";  -- Write Protect Mask
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  constant WQL_Address              : ADDRESS_TYPE := x"1100";  -- Write Qual Register
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  constant INT_Address              : ADDRESS_TYPE := x"1200";  -- Interrupt Manager
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  constant ROM_Address              : ADDRESS_TYPE := x"8000";  -- Application ROM
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  constant ISR_Start_Addr           : ADDRESS_TYPE := x"FFF0";  -- ISR vector table
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  -- RAM size is used to calculate the initial stack pointer, which is set at
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  --  the top of the RAM region.
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  constant RAM_Size                 : integer   := 4096;
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  constant RAM_Write_Protect        : boolean   := TRUE;
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  -- CPU Interrupt assignments - Note that interrupt 0 is the NMI (non-maskable)
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  --  also, because these are handled by the CPU, they are in priority order
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  --  from 0 (highest) to 7 (lowest).
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  constant CPU_INT_RAM              : integer range 0 to OPEN8_DATA_WIDTH - 1 := 0;
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  constant CPU_INT_PIT              : integer range 0 to OPEN8_DATA_WIDTH - 1 := 1;
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  constant CPU_INT_EXT              : integer range 0 to OPEN8_DATA_WIDTH - 1 := 2;
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  -- I/O Interrupt assignments (Not technically required, as software will overwrite
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  --  this during initialization)
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  constant Default_IO_Int_Mask      : ADDRESS_TYPE := x"0000";
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  -- Set this to the number of readable modules in the design, as it sets the
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  --  number of ports on the read aggregator function.
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  constant NUM_READ_BUSES           : integer := 4;
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  -- Read Data Bus aggregator and bus assignments.
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  --  Note that the ordering isn't important, only that each device has a
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  --   unique number less than NUM_READ_BUSES.
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  constant RDB_RAM                  : integer range 0 to NUM_READ_BUSES - 1   :=  0;
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  constant RDB_WQL                  : integer range 0 to NUM_READ_BUSES - 1   :=  1;
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  constant RDB_INT                  : integer range 0 to NUM_READ_BUSES - 1   :=  2;
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  constant RDB_ROM                  : integer range 0 to NUM_READ_BUSES - 1   :=  3;
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  -- System configuration calculations - no adjustable parameters below this point
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  type OPEN8_BUS_ARRAY is array(0 to NUM_READ_BUSES - 1) of DATA_TYPE;
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  constant INIT_READ_BUS            : OPEN8_BUS_ARRAY := (others => OPEN8_NULLBUS);
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  function merge_buses (x : in OPEN8_BUS_ARRAY) return DATA_TYPE;
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  -- Compute the stack start address based on the RAM size
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  constant RAM_Vector_Size          : integer := ceil_log2(RAM_Size - 1);
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  constant RAM_End_Addr             : std_logic_vector(RAM_Vector_Size - 1 downto 0)
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                                     := (others => '1');
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  constant Stack_Start_Addr         : ADDRESS_TYPE := RAM_Address + RAM_End_Addr;
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end package;
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package body open8_cfg is
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  function merge_buses (x : in OPEN8_BUS_ARRAY) return DATA_TYPE is
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    variable i               : integer   := 0;
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    variable retval          : DATA_TYPE := x"00";
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  begin
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    retval                   := x"00";
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    for i in 0 to NUM_READ_BUSES - 1 loop
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      retval                 := retval or x(i);
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    end loop;
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    return retval;
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  end function;
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end package body;

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