pack_mips.vhd

这是一个基于mips-I结构的处理器,32bit,冯诺依曼结构

------------------------------------------------------------------------------------
--                                                                                --
--    Copyright (c) 2004, Hangouet Samuel                                         --
--                  , Jan Sebastien                                               --
--                  , Mouton Louis-Marie                                          --
--                  , Schneider Olivier     all rights reserved                   --
--                                                                                --
--    This file is part of miniMIPS.                                              --
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--    miniMIPS is free software; you can redistribute it and/or modify            --
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--    You should have received a copy of the GNU General Public License           --
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------------------------------------------------------------------------------------


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--------------------------------------------------------------------------
--                                                                      --
--                                                                      --
--     Processor miniMIPS : Enumerations and components declarations    --
--                                                                      --
--                                                                      --
--                                                                      --
-- Authors : Hangouet  Samuel                                           --
--           Jan       S閎astien                                        --
--           Mouton    Louis-Marie                                      --
--           Schneider Olivier                                          --
--                                                                      --
--                                                          june 2003   --
--------------------------------------------------------------------------


library ieee;
use ieee.std_logic_1164.all;

package pack_mips is		    

    -- Type signal on n bits
    subtype bus64 is std_logic_vector(63 downto 0);
    subtype bus33 is std_logic_vector(32 downto 0);
    subtype bus32 is std_logic_vector(31 downto 0);
    subtype bus31 is std_logic_vector(30 downto 0);
    subtype bus26 is std_logic_vector(25 downto 0);
    subtype bus24 is std_logic_vector(23 downto 0);
    subtype bus16 is std_logic_vector(15 downto 0);
    subtype bus8 is std_logic_vector(7 downto 0);
    subtype bus6 is std_logic_vector(5 downto 0);
    subtype bus5 is std_logic_vector(4 downto 0);
    subtype bus4 is std_logic_vector(3 downto 0);
    subtype bus2 is std_logic_vector(1 downto 0);
    subtype bus1 is std_logic;

    -- Address of a register type
    subtype adr_reg_type is std_logic_vector(5 downto 0);

    -- Coding of the level of data availability for UR
    subtype level_type is std_logic_vector(1 downto 0);
    constant LVL_DI  : level_type := "11";  -- Data available from the op2 of DI stage
    constant LVL_EX  : level_type := "10";  -- Data available from the data_ual register of EX stage
    constant LVL_MEM : level_type := "01";  -- Data available from the data_ecr register of MEM stage
    constant LVL_REG : level_type := "00";  -- Data available only in the register bank

    -- Different values of cause exceptions
    constant IT_NOEXC : bus32 := X"00000000";
    constant IT_ITMAT : bus32 := X"00000001";
    constant IT_OVERF : bus32 := X"00000002";
    constant IT_ERINS : bus32 := X"00000004";
    constant IT_BREAK : bus32 := X"00000008";
    constant IT_SCALL : bus32 := X"00000010";


    -- Operation type of the coprocessor system (only the low 16 bits are valid)
    constant SYS_NOP    : bus32 := X"0000_0000";
    constant SYS_MASK   : bus32 := X"0000_0001";
    constant SYS_UNMASK : bus32 := X"0000_0002";
    constant SYS_ITRET  : bus32 := X"0000_0004";

    -- Type for the alu control
    subtype alu_ctrl_type is std_logic_vector(27 downto 0);

    -- Arithmetical operations
    constant OP_ADD   : alu_ctrl_type := "1000000000000000000000000000"; -- op1 + op2 sign