Subversion Repositories cpu_lecture

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

-- 

-- Copyright (C) 2009, 2010 Dr. Juergen Sauermann

-- 

--  This code is free software: you can redistribute it and/or modify

--  it under the terms of the GNU General Public License as published by

--  the Free Software Foundation, either version 3 of the License, or

--  (at your option) any later version.

--

--  This code is distributed in the hope that it will be useful,

--  but WITHOUT ANY WARRANTY; without even the implied warranty of

--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

--  GNU General Public License for more details.

--

--  You should have received a copy of the GNU General Public License

--  along with this code (see the file named COPYING).

--  If not, see http://www.gnu.org/licenses/.

--

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

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

--  

-- Module Name:    common

-- Create Date:    13:51:24 11/07/2009 

-- Description:    constants shared by different modules.

--

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

--

library IEEE;

use IEEE.STD_LOGIC_1164.all;

package common is

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

    -- ALU operations

    --

    constant ALU_ADC    : std_logic_vector(4 downto 0) := "00000";

    constant ALU_ADD    : std_logic_vector(4 downto 0) := "00001";

    constant ALU_ADIW   : std_logic_vector(4 downto 0) := "00010";

    constant ALU_AND    : std_logic_vector(4 downto 0) := "00011";

    constant ALU_ASR    : std_logic_vector(4 downto 0) := "00100";

    constant ALU_BLD    : std_logic_vector(4 downto 0) := "00101";

    constant ALU_BIT_CS : std_logic_vector(4 downto 0) := "00110";

    constant ALU_COM    : std_logic_vector(4 downto 0) := "00111";

    constant ALU_DEC    : std_logic_vector(4 downto 0) := "01000";

    constant ALU_EOR    : std_logic_vector(4 downto 0) := "01001";

    constant ALU_MV_16  : std_logic_vector(4 downto 0) := "01010";

    constant ALU_INC    : std_logic_vector(4 downto 0) := "01011";

    constant ALU_INTR   : std_logic_vector(4 downto 0) := "01100";

    constant ALU_LSR    : std_logic_vector(4 downto 0) := "01101";

    constant ALU_D_MV_Q : std_logic_vector(4 downto 0) := "01110";

    constant ALU_R_MV_Q : std_logic_vector(4 downto 0) := "01111";

    constant ALU_MULT   : std_logic_vector(4 downto 0) := "10000";

    constant ALU_NEG    : std_logic_vector(4 downto 0) := "10001";

    constant ALU_OR     : std_logic_vector(4 downto 0) := "10010";

    constant ALU_PC_1   : std_logic_vector(4 downto 0) := "10011";

    constant ALU_PC_2   : std_logic_vector(4 downto 0) := "10100";

    constant ALU_ROR    : std_logic_vector(4 downto 0) := "10101";

    constant ALU_SBC    : std_logic_vector(4 downto 0) := "10110";

    constant ALU_SBIW   : std_logic_vector(4 downto 0) := "10111";

    constant ALU_SREG   : std_logic_vector(4 downto 0) := "11000";

    constant ALU_SUB    : std_logic_vector(4 downto 0) := "11001";

    constant ALU_SWAP   : std_logic_vector(4 downto 0) := "11010";

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

    --

    -- PC manipulations

    --

    constant PC_NEXT    : std_logic_vector(2 downto 0) := "000";    -- PC += 1

    constant PC_BCC     : std_logic_vector(2 downto 0) := "001";    -- PC ?= IMM

    constant PC_LD_I    : std_logic_vector(2 downto 0) := "010";    -- PC = IMM

    constant PC_LD_Z    : std_logic_vector(2 downto 0) := "011";    -- PC = Z

    constant PC_LD_S    : std_logic_vector(2 downto 0) := "100";    -- PC = (SP)

    constant PC_SKIP_Z  : std_logic_vector(2 downto 0) := "101";    -- SKIP if Z

    constant PC_SKIP_T  : std_logic_vector(2 downto 0) := "110";    -- SKIP if T

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

    --

    -- Addressing modes. An address mode consists of two sub-fields,

    -- which are the source of the address and an offset from the source.

    -- Bit 3 indicates if the address will be modified.

    -- address source

    constant AS_SP  : std_logic_vector(2 downto 0) := "000";     -- SP

    constant AS_Z   : std_logic_vector(2 downto 0) := "001";     -- Z

    constant AS_Y   : std_logic_vector(2 downto 0) := "010";     -- Y

    constant AS_X   : std_logic_vector(2 downto 0) := "011";     -- X

    constant AS_IMM : std_logic_vector(2 downto 0) := "100";     -- IMM

    -- address offset

    constant AO_0   : std_logic_vector(5 downto 3) := "000";     -- as is

    constant AO_Q   : std_logic_vector(5 downto 3) := "010";     -- +q

    constant AO_i   : std_logic_vector(5 downto 3) := "001";     -- +1

    constant AO_ii  : std_logic_vector(5 downto 3) := "011";     -- +2

    constant AO_d   : std_logic_vector(5 downto 3) := "101";     -- -1

    constant AO_dd  : std_logic_vector(5 downto 3) := "111";     -- -2

    --                                                   |

    --                                                +--+

    -- address updated ?                              |

    --                                                v

    constant AM_WX : std_logic_vector(3 downto 0) := '1' & AS_X;  -- X ++ or --

    constant AM_WY : std_logic_vector(3 downto 0) := '1' & AS_Y;  -- Y ++ or --

    constant AM_WZ : std_logic_vector(3 downto 0) := '1' & AS_Z;  -- Z ++ or --

    constant AM_WS : std_logic_vector(3 downto 0) := '1' & AS_SP; -- SP ++/--

    -- address modes used

    --

    constant AMOD_ABS : std_logic_vector(5 downto 0) := AO_0  & AS_IMM; -- IMM

    constant AMOD_X   : std_logic_vector(5 downto 0) := AO_0  & AS_X;   -- (X)

    constant AMOD_Xq  : std_logic_vector(5 downto 0) := AO_Q  & AS_X;   -- (X+q)

    constant AMOD_Xi  : std_logic_vector(5 downto 0) := AO_i  & AS_X;   -- (X++)

    constant AMOD_dX  : std_logic_vector(5 downto 0) := AO_d  & AS_X;   -- (--X)

    constant AMOD_Y   : std_logic_vector(5 downto 0) := AO_0  & AS_Y;   -- (Y)

    constant AMOD_Yq  : std_logic_vector(5 downto 0) := AO_Q  & AS_Y;   -- (Y+q)

    constant AMOD_Yi  : std_logic_vector(5 downto 0) := AO_i  & AS_Y;   -- (Y++)

    constant AMOD_dY  : std_logic_vector(5 downto 0) := AO_d  & AS_Y;   -- (--Y)

    constant AMOD_Z   : std_logic_vector(5 downto 0) := AO_0  & AS_Z;   -- (Z)

    constant AMOD_Zq  : std_logic_vector(5 downto 0) := AO_Q  & AS_Z;   -- (Z+q)

    constant AMOD_Zi  : std_logic_vector(5 downto 0) := AO_i  & AS_Z;   -- (Z++)

    constant AMOD_dZ  : std_logic_vector(5 downto 0) := AO_d  & AS_Z;   -- (--Z)

    constant AMOD_SPi : std_logic_vector(5 downto 0) := AO_i  & AS_SP;  -- (SP++)

    constant AMOD_SPii: std_logic_vector(5 downto 0) := AO_ii & AS_SP;  -- (SP++)

    constant AMOD_dSP : std_logic_vector(5 downto 0) := AO_d  & AS_SP;  -- (--SP)

    constant AMOD_ddSP: std_logic_vector(5 downto 0) := AO_dd & AS_SP;  -- (--SP)

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

    -- Stack pointer manipulations.

    --

    constant SP_NOP : std_logic_vector(2 downto 0) := "000";

    constant SP_ADD1: std_logic_vector(2 downto 0) := "001";

    constant SP_ADD2: std_logic_vector(2 downto 0) := "010";

    constant SP_SUB1: std_logic_vector(2 downto 0) := "011";

    constant SP_SUB2: std_logic_vector(2 downto 0) := "100";

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

    --

    -- ALU multiplexers.

    --

    constant RS_REG : std_logic_vector(1 downto 0) := "00";

    constant RS_IMM : std_logic_vector(1 downto 0) := "01";

    constant RS_DIN : std_logic_vector(1 downto 0) := "10";

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

    --

    -- Multiplier variants. F means FMULT (as opposed to MULT).

    -- S and U means signed vs. unsigned operands.

    --

    constant MULT_UU  : std_logic_vector(2 downto 0) := "000";

    constant MULT_SU  : std_logic_vector(2 downto 0) := "010";

    constant MULT_SS  : std_logic_vector(2 downto 0) := "011";

    constant MULT_FUU : std_logic_vector(2 downto 0) := "100";

    constant MULT_FSU : std_logic_vector(2 downto 0) := "110";

    constant MULT_FSS : std_logic_vector(2 downto 0) := "111";

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

end common;