402 lines
18 KiB
VHDL
402 lines
18 KiB
VHDL
-------------------------------------------------------
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--! @file
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--! @brief the control unit for the Simple Processor Core (Geraffel Processor)
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--! @author Dominik Meyer
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--! @email dmeyer@hsu-hh.de
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--! @licence GPLv2
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--! @date 2010-11-19
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-------------------------------------------------------
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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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library work;
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use work.cpupkg.all;
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--! the control unit for the Simple Processor Core (Geraffel Processor)
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--!
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--! This Code is based on a processor core used at the Helmut Schmidt University for
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--! educational purposes.
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--!
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entity ControlUnit is
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port (
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iClk : in std_logic; --! iClk signal
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iReset : in std_logic; --! iReset signal
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icOpCode : in optype; --! icOpCode bus
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idCarry : in std_logic; --! carry from register file
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idZero : in std_logic; --! zero flag from register file
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ocRnotWRam : out std_logic; --! r_notw to RAM
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ocLoadEn : out std_logic; --! safe result of alu
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ocEnableRAM : out std_logic; --! put akku on databus
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ocLoadInstr : out std_logic; --! load instruction control signal
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ocNextPC : out std_logic; --! increment pc
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ocAddrSel : out std_logic; --! pc on addressbus
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ocJump : out std_logic; --! do a ocJump
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ocPCregister : out std_logic; --! put PC to register File
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ocUsePC : out std_logic; --! use Register to fill in the PC
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ocLoad : out std_logic --! put databus to ALU immediate port
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);
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end ControlUnit;
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architecture arch of ControlUnit is
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type STATES is (load, decode, exshl, exshr, exsto, exloa, exloa2, exli, exadd, exsub, exaddc, exsubc,
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exopor, exopand, exopxor, exopnot, exjpz, exjpc, exjmp, exhlt, exjmc, exret);
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signal sState, sState_next : STATES;
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begin
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--! switch sStates if needed
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sState_change : process(iClk,iReset)
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begin
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if (iReset = '1') then
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sState <= load;
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elsif (rising_edge(iClk)) then
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sState <= sState_next;
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end if;
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end process;
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--! calculate the next state of the FSM
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calc_sState_next : process(sState, icOpCode, idCarry, idZero)
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begin
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case sState is
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when load =>
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sState_next <= decode;
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when decode =>
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case icOpCode is
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when shl => sState_next <= exshl;
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when shr => sState_next <= exshr;
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when sto => sState_next <= exsto;
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when loa => sState_next <= exloa;
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when li => sState_next <= exli;
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when add => sState_next <= exadd;
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when sub => sState_next <= exsub;
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when addc => sState_next <= exaddc;
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when subc => sState_next <= exsubc;
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when opand => sState_next <= exopand;
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when opor => sState_next <= exopor;
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when opxor => sState_next <= exopxor;
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when opnot => sState_next <= exopnot;
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when jpz =>
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if (idZero = '1') then
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sState_next <= exjpz;
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else
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sState_next <= load;
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end if;
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when jpc =>
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if (idCarry = '1') then
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sState_next <= exjpc;
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else
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sState_next <= load;
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end if;
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when jmp => sState_next <= exjmp;
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when jmc => sState_next <= exjmc;
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when ret => sState_next <= exret;
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when hlt => sState_next <= exhlt;
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end case;
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when exhlt => sState_next <= exhlt;
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when exloa => sState_next <= exloa2;
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when others => sState_next <= load;
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end case;
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end process;
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--! calculate the output in each sState
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calc_output : process(sState)
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begin
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case sState is
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when load =>
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ocRnotWRam <= '1'; -- read from RAM
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ocLoadEn <= '0'; -- do not save result
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ocEnableRAM <= '1'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- load instruction
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ocNextPC <= '0'; -- do not increment pc
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ocAddrSel <= '1'; -- pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when decode =>
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ocRnotWRam <= '1'; -- read from RAM
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ocLoadEn <= '0'; -- do not save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '1'; -- load instruction
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ocNextPC <= '1'; -- do not increment pc
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ocAddrSel <= '0'; -- pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exshl =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exshr =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exsto =>
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ocRnotWRam <= '0'; -- write to RAM
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ocLoadEn <= '0'; -- do not save result
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ocEnableRAM <= '1'; -- put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exloa =>
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ocRnotWRam <= '1'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '1'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exli =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exadd =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exsub =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exaddc =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exloa2 =>
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ocRnotWRam <= '1'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '1'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '1';
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when exsubc =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exopor =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exopand =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exopxor =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exopnot =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exjpz =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '0'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '1'; -- ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exjpc =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '0'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '1'; -- ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exjmp =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '0'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '1'; -- ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exjmc =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '1'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '1'; -- ocJump
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ocPCregister <= '1'; -- put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when exret =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '0'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- ocJump
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ocPCregister <= '0'; -- put PC to register File
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ocUsePC <= '1';
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ocLoad <= '0';
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when exhlt =>
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ocRnotWRam <= '0'; -- read from RAM
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ocLoadEn <= '0'; -- save result
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ocEnableRAM <= '0'; -- do not put akku on databus
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ocLoadInstr <= '0'; -- do not load instruction
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ocNextPC <= '0'; -- increment pc
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ocAddrSel <= '0'; -- no pc on addressbus
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ocJump <= '0'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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when others =>
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ocRnotWRam <= '-'; -- read from RAM
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ocLoadEn <= '-'; -- save result
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ocEnableRAM <= '-'; -- do not put akku on databus
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ocLoadInstr <= '-'; -- do not load instruction
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ocNextPC <= '-'; -- increment pc
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ocAddrSel <= '-'; -- no pc on addressbus
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ocJump <= '-'; -- no ocJump
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ocPCregister <= '0'; -- do not put PC to register File
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ocUsePC <= '0';
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ocLoad <= '0';
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end case;
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end process;
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end arch;
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