FIX: fixed file headers, added licence, formated code

src/ALU.vhd

@@ -1,60 +1,59 @@
-----------------------------------------------------------------------------------
+-------------------------------------------------------
--- Company: 
+--! @file 
--- Engineer: 
+--! @brief Simple ALU for the Simple Processor Core (Geraffel Processor)
--- 
+--! @author Dominik Meyer/ Marcel Eckert
--- Create Date:    15:13:27 05/10/2011 
+--! @email dmeyer@federationhq.de
--- Design Name: 
+--! @licence GPLv2
--- Module Name:    ALU - Behavioral 
+--! @date unknown
--- Project Name: 
+-------------------------------------------------------
--- Target Devices: 
+
--- Tool versions: 
--- Description: 
---
--- Dependencies: 
---
--- Revision: 
--- Revision 0.01 - File Created
--- Additional Comments: 
---
-----------------------------------------------------------------------------------
 library IEEE;
-use IEEE.STD_LOGIC_1164.ALL;
+    use IEEE.STD_LOGIC_1164.all;
-use IEEE.STD_LOGIC_UNSIGNED.ALL;
+    use IEEE.STD_LOGIC_UNSIGNED.all;
 
 library work;
     use work.cpupkg.all;
--- Uncomment the following library declaration if using
--- arithmetic functions with Signed or Unsigned values
---use IEEE.NUMERIC_STD.ALL;
 
--- Uncomment the following library declaration if instantiating
+
--- any Xilinx primitives in this code.
+--! A very Simple ALU to support all the arithmetical and logical operation of the
---library UNISIM;
+--! Simple Processor Core (Geraffel Processor Core)
---use UNISIM.VComponents.all;
+--! 
+--! This Code is based on a processor core used at the Helmut Schmidt University for
+--! educational purposes.
+--!
+
 
 entity ALU is
-	Port(
+    port(
-		idOperand1	: in  DATA;
+        idOperand1  : in    DATA;            --! first Operand for any operation
-		idOperand2	: in  DATA;
+        idOperand2  : in    DATA;            --! second Operand for any operation
-		idCarryIn	: in  std_logic;
+        idCarryIn   : in    std_logic;       --! Carry Input for any arithmetical operation
-		idImmidiate : in  DATA;
+        idImmidiate : in    DATA;            --! Immediate input for operation requiring an immediat
-		
+        odResult    : out   DATA;            --! Result output of any operation
-		odResult		: out DATA;
+        odCarryOut  : out   std_logic;       --! Output of the Carry, if generated by an operation
-		odCarryOut	: out std_logic;
+        odZeroOut   : out   std_logic;       --! is the result zero flag output
-		odZeroOut	: out std_logic;
+        icOperation : in    OPTYPE           --! which Operation to perform
-		
-		icOperation	: in  OPTYPE
     );
 end ALU;
 
+
+--! Architectural description of the ALU
 architecture Behavioral of ALU is
     signal sdTempResult, sdOp1, sdOp2 : std_logic_vector(32 downto 0);
 begin
+
+    -- extend the operand by one bit, to be able to get the overflow
+    -- of an operation
     sdOp1 <= '0' & idOperand1;
     sdOp2 <= '0' & idOperand2;
 
+
+    --! process to do the actual computation
     process (sdOp1, sdOp2, idCarryIn, icOperation, idImmidiate, idOperand1)
     begin
+
+        -- TODO: convert to case structure for improved space usege and speed
+
         if (icOperation = shl) then
             sdTempResult <= sdOp1(31 downto 0) & "0";
 
@@ -107,10 +106,11 @@ begin
         end if;
     end process;
 
+
+    -- output the generated signals 
     odResult   <= sdTempResult(31 downto 0);
     odCarryOut <= sdTempResult(32);
     odZeroOut  <= '1' when sdTempResult(31 downto 0) = 0 else
                         '0';
 
 end Behavioral;
-

src/ControlUnit.vhd

@@ -1,12 +1,11 @@
 -------------------------------------------------------
 --! @file 
---! @brief the control unit of the IIB2 Akkumulator machine
+--! @brief the control unit for the Simple Processor Core (Geraffel Processor)
 --! @author Dominik Meyer
 --! @email dmeyer@hsu-hh.de
+--! @licence GPLv2
 --! @date 2010-11-19
 -------------------------------------------------------
-
-
 library ieee;
     use ieee.std_logic_1164.all;
     use ieee.std_logic_unsigned.all;
@@ -14,7 +13,14 @@ use ieee.std_logic_unsigned.all;
 library work;
     use work.cpupkg.all;
 
-entity Steuerwerk is
+
+--! the control unit for the Simple Processor Core (Geraffel Processor)
+--! 
+--! This Code is based on a processor core used at the Helmut Schmidt University for
+--! educational purposes.
+--!
+
+entity ControlUnit is
     port  (
         iClk         : in     std_logic;        --! iClk signal
         iReset       : in     std_logic;        --! iReset signal
@@ -32,21 +38,23 @@ entity Steuerwerk is
         ocUsePC      : out    std_logic;        --! use Register to fill in the PC
         ocLoad       : out    std_logic         --! put databus to ALU immediate port
     );
-end Steuerwerk;
+end ControlUnit;
 
-architecture arch of Steuerwerk is
+architecture arch of ControlUnit is
 
-type STATES	is (load, decode, exshl, exshr, exsto, exloa, exli, exadd, exsub, exaddc, exsubc, 
+    type STATES    is (load, decode, exshl, exshr, exsto, exloa, exloa2, exli, exadd, exsub, exaddc, exsubc,
         exopor, exopand, exopxor, exopnot, exjpz, exjpc, exjmp, exhlt, exjmc, exret);
 
     signal sState, sState_next : STATES;
 
 begin
 
--- switch sStates if needed
+
+--! switch sStates if needed
     sState_change : process(iClk,iReset)
     begin
         if (iReset = '1') then
+
             sState <= load;
 
         elsif (rising_edge(iClk)) then
@@ -55,6 +63,7 @@ begin
     end process;
 
 
+--! calculate the next state of the FSM
     calc_sState_next : process(sState, icOpCode, idCarry, idZero)
     begin
 
@@ -76,12 +85,14 @@ begin
                     when opor  => sState_next <= exopor;
                     when opxor => sState_next <= exopxor;
                     when opnot => sState_next <= exopnot;
-							when jpz		=> if (idZero = '1') then
+                    when jpz   => 
+                        if (idZero = '1') then
                             sState_next <= exjpz;
                         else
                             sState_next <= load;
                         end if;
-							when jpc		=> if (idCarry = '1') then
+                    when jpc => 
+                        if (idCarry = '1') then
                             sState_next <= exjpc;
                         else
                             sState_next <= load;
@@ -92,6 +103,7 @@ begin
                     when hlt => sState_next <= exhlt;
                 end case;
             when exhlt  => sState_next <= exhlt;
+            when exloa  => sState_next <= exloa2;
             when others => sState_next <= load;
         end case;
 
@@ -175,7 +187,8 @@ begin
                 ocJump       <= '0';    -- no ocJump
                 ocPCregister <= '0';    -- do not put PC to register File
                 ocUsePC      <= '0';
-		                ocLoad          <= '1';
+                ocLoad       <= '0';
+
 
             when exli    =>
                 ocRnotWRam   <= '0';    -- read from RAM
@@ -224,6 +237,17 @@ begin
                 ocPCregister <= '0';    -- do not put PC to register File
                 ocUsePC      <= '0';
                 ocLoad       <= '0';
+            when exloa2    =>
+                ocRnotWRam   <= '1';    -- read from RAM
+                ocLoadEn     <= '1';    -- save result
+                ocEnableRAM  <= '1';    -- do not put akku on databus
+                ocLoadInstr  <= '0';    -- do not load instruction
+                ocNextPC     <= '0';    -- increment pc
+                ocAddrSel    <= '0';    -- no pc on addressbus
+                ocJump       <= '0';    -- no ocJump
+                ocPCregister <= '0';    -- do not put PC to register File
+                ocUsePC      <= '0';
+                ocLoad       <= '1';
 
             when exsubc    =>
                 ocRnotWRam   <= '0';    -- read from RAM
@@ -375,22 +399,3 @@ end process;
 
 
 end arch;
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-

src/FetchDecode.vhd

@@ -1,57 +1,44 @@
-----------------------------------------------------------------------------------
+-------------------------------------------------------
--- Company: 
+--! @file 
--- Engineer: 
+--! @brief Fetch/Decode Component  for the Simple Processor Core (Geraffel Processor)
--- 
+--! @author Dominik Meyer/ Marcel Eckert
--- Create Date:    16:16:43 05/10/2011 
+--! @email dmeyer@federationhq.de
--- Design Name: 
+--! @licence GPLv2
--- Module Name:    FetchDecode - Behavioral 
+--! @date unknown
--- Project Name: 
+-------------------------------------------------------
--- Target Devices: 
--- Tool versions: 
--- Description: 
---
--- Dependencies: 
---
--- Revision: 
--- Revision 0.01 - File Created
--- Additional Comments: 
---
-----------------------------------------------------------------------------------
 library IEEE;
-use IEEE.STD_LOGIC_1164.ALL;
+    use IEEE.STD_LOGIC_1164.all;
-use IEEE.STD_LOGIC_UNSIGNED.ALL;
+    use IEEE.STD_LOGIC_UNSIGNED.all;
 
 library work;
     use work.cpupkg.all;
 
--- Uncomment the following library declaration if using
+--! Fetch/Decode Component for the Simple Processor Core (Geraffel Processor)
--- arithmetic functions with Signed or Unsigned values
+--! 
---use IEEE.NUMERIC_STD.ALL;
+--! This Code is based on a processor core used at the Helmut Schmidt University for
-
+--! educational purposes.
--- Uncomment the following library declaration if instantiating
+--!
--- any Xilinx primitives in this code.
---library UNISIM;
---use UNISIM.VComponents.all;
 
 entity FetchDecode is
-	Port(
+    port(
-		iClk			: in  std_logic;
-		iReset		: in  std_logic;
 
-		idData		: in  DATA;
+        iClk          : in  std_logic;                       --! main system clock
-		icAddrSel	: in  std_logic;
+        iReset        : in  std_logic;                       --! system active high reset
-		icLoadInstr	: in  std_logic;
+
-		icJump		: in  std_logic;
+        idData        : in  DATA;                            --! Data input coming from the RAM with instruction
-		icNextPC	: in  std_logic;
+        icAddrSel     : in  std_logic;                       --! Put AddressRegister to Address BUS
-		odPC        : out ADDRESS;  
+        icDecodeInstr : in  std_logic;                       --! Decode the loaded instrcution
-		idPC        : in  ADDRESS;
+        icJump        : in  std_logic;                       --! executed instruction is a jump, put jump register to address bus
-		icUsePC     : in  std_logic;
+        icNextPC      : in  std_logic;                       --! increment the PC
-		odAddress	: out ADDRESS;
+        odPC          : out ADDRESS;                         --! put out the current PC
-		odImmidiate : out DATA;
+        idPC          : in  ADDRESS;                         --! input for a new PC from extern
-		odRegAsel   : out std_logic_vector(4 downto 0);
+        icUsePC       : in  std_logic;                       --! use the external PC
-		odRegBsel   : out std_logic_vector(4 downto 0);
+        odAddress     : out ADDRESS;                         --! output to the address bus
-		odRegINsel  : out std_logic_vector(4 downto 0);
+        odImmidiate   : out DATA;                            --! output the loaded immediate
-		ocOperation	: out OPTYPE
+        odRegAsel     : out std_logic_vector(4 downto 0);    --! output the decoded register addr
+        odRegBsel     : out std_logic_vector(4 downto 0);    --! output the decoded register addr
+        odRegINsel    : out std_logic_vector(4 downto 0);    --! output the decoded result register addr
+        ocOperation   : out OPTYPE                           --! output which operation to perform
 
     );
 end FetchDecode;
@@ -68,26 +55,33 @@ architecture Behavioral of FetchDecode is
     signal scOp, scOp_next : OPTYPE;
 
 begin
-	Transition: process(idData, sdImmidate, icLoadInstr, icJump, icNextPC, sdAdr, sdPC, scOp, sdRegAsel, sdRegBsel, sdRegINsel, icUsePC, idPC)
+
+    Transition : process(idData, sdImmidate, icDecodeInstr, icJump, icNextPC, sdAdr, sdPC, scOp, sdRegAsel, sdRegBsel, sdRegINsel, icUsePC, idPC)
     begin
-		-- defaults
+
+        -- default values for all signals/registers
         sdAdr_next       <= sdAdr;
         sdPC_next        <= sdPC;
         scOp_next        <= scOp;
         sdImmidiate_next <= sdImmidate;
 
+        -- fill the next register values with the old ones
         sdRegAsel_next  <= sdRegAsel;
         sdRegBsel_next  <= sdRegBsel;
         sdRegINsel_next <= sdRegINsel;
 
-        --! ISA Definition	    
+        --! ISA Definition, for the Decode run
-		if (icLoadInstr = '1') then
+        if (icDecodeInstr = '1') then
+
+            -- because of the fixed bit positions we can fill in the correct values to the next register values
             sdAdr_next       <= idData(15 downto 0);
             sdImmidiate_next <= "0000000000000000" & idData(15 downto 0);
             sdRegINsel_next  <= idData(25 downto 21);
             sdRegAsel_next   <= idData(20 downto 16);
             sdRegBsel_next   <= idData(15 downto 11);
 
+
+            -- select the operation to do according to the decoded opcode
             case idData(31 downto 26) is
                 when "000000" => scOp_next <= shl;
                 when "000001" => scOp_next <= shr;
@@ -111,6 +105,7 @@ begin
             end case;
         end if;
 
+        -- set registers according of some special external control signals
         if (icUsePC = '1') then
             sdPC_next <= idPC;
         end if;
@@ -128,7 +123,7 @@ begin
     end process;
 
 
-	-- Execute Transition
+    -- Execute Transition, set register values to the calculated next register values
     process(iClk, iReset)
     begin
         if (iReset = '1') then
@@ -153,7 +148,7 @@ begin
 
     end process;
 
-	-- Output
+    -- Output everything to the correct output signal
     odAddress <= idPC  when icUsePC = '1' else
                    sdAdr when icAddrSel = '0' and icLoadInstr = '0' else
                    sdAdr_next when icAddrSel = '0' and icLoadInstr = '1' else
@@ -172,4 +167,3 @@ begin
 
 
 end Behavioral;
-

src/MemoryMapper.vhd

@@ -2,11 +2,9 @@
 --! @file 
 --! @brief Maps memory devices to a given memory space
 --! @author Dominik Meyer
---! @email dmeyer@hsu-hh.de
+--! @email dmeyer@federationhq.de
 --! @date 2010-06-03
 -------------------------------------------------------
-
-
 library ieee;
     use ieee.std_logic_1164.all;
     use ieee.std_logic_unsigned.all;
@@ -17,9 +15,7 @@ entity MemoryMapper is
     port(
         start   : in    std_logic_vector(15 downto 0);           --! start of memory space
         stop    : in    std_logic_vector(15 downto 0);           --! end of mempry space
-            
         adr_in  : in    std_logic_vector(15 downto 0);
-            
         req_in  : in    std_logic;                               --! ram request type
         req_out : out   std_logic;                               --! ram request type
 
@@ -51,4 +47,3 @@ begin
     end process;
 
 end arch;
-

src/RegFile.vhd

@@ -1,53 +1,47 @@
-----------------------------------------------------------------------------------
+-------------------------------------------------------
--- Company: 
+--! @file 
--- Engineer: 
+--! @brief RegisterFile for the Simple Processor Core (Geraffel Processor)
--- 
+--! @author Dominik Meyer
--- Create Date:    16:05:19 05/10/2011 
+--! @email dmeyer@federationhq.de
--- Design Name: 
+--! @licence GPLv2
--- Module Name:    RegFile - Behavioral 
+--! @date unknown
--- Project Name: 
+-------------------------------------------------------
--- Target Devices: 
--- Tool versions: 
--- Description: 
---
--- Dependencies: 
---
--- Revision: 
--- Revision 0.01 - File Created
--- Additional Comments: 
---
-----------------------------------------------------------------------------------
 library IEEE;
-use IEEE.STD_LOGIC_1164.ALL;
+    use IEEE.STD_LOGIC_1164.all;
 
 library work;
     use work.cpupkg.all;
     use ieee.numeric_std.all;
 
+--! RegisterFile for the Simple Processor Core (Geraffel Processor)
+--! 
+--! This Code is based on a processor core used at the Helmut Schmidt University for
+--! educational purposes.
+--!
 
 entity RegFile is
-	Port(
+    port(
-		iClk			: in  std_logic;
+        iClk        : in    std_logic;                       --! main sytem clock signal
-		iReset		    : in  std_logic;
+        iReset      : in    std_logic;                       --! main system active high reset
 
-	    icRegAsel       : in  std_logic_vector(4 downto 0);  
+        icRegAsel   : in    std_logic_vector(4 downto 0);    --! address of register A
-	    icRegBsel       : in  std_logic_vector(4 downto 0);
+        icRegBsel   : in    std_logic_vector(4 downto 0);    --! address of register B
-	    odRegA          : out DATA;
+        odRegA      : out   DATA;                            --! output of the register A Value
-	    odRegB          : out DATA;
+        odRegB      : out   DATA;                            --! output of the register B Value
 
-	    icPC            :  in std_logic;   -- select PC as input to RegisterFile
+        icPC        : in    std_logic;                       --! select the PC Input as the input value, required for ret instruction
-	    idPC            :  in DATA;
+        idPC        : in    DATA;                            --! input of the PC, required for the ret instruction
 
-	    icRegINsel      : in  std_logic_vector(4 downto 0);
+        icRegINsel  : in    std_logic_vector(4 downto 0);    --! address of the register to which to save the input
 
-		idDataIn		: in  DATA;
+        idDataIn    : in    DATA;                            --! data input, normally from the ALU
-		idCarryIn	: in  std_logic;
+        idCarryIn   : in    std_logic;                           --! Carry Flag of the last Operation
-		idZeroIn		: in  std_logic;
+        idZeroIn    : in    std_logic;                       --! Zero Flag of the last Operation
 
-		icLoadEn		: in std_logic;
+        icLoadEn    : in    std_logic;                       --! actually save the input Data to the selected register
 
-		odCarryOut	: out std_logic;
+        odCarryOut  : out   std_logic;                       --! output of the currently saved carry flag
-		odZeroOut	: out	std_logic
+        odZeroOut   : out   std_logic                        --! output of the currently saved zero flag
     );
 end RegFile;
 
@@ -99,4 +93,3 @@ begin
     odZeroOut  <= sdZero;
 
 end Behavioral;
-