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-- VHDL Entity work.FPadd_normalize.symbol

--

-- Created by

-- Guillermo Marcus, gmarcus@ieee.org

-- using Mentor Graphics FPGA Advantage tools.

--

-- Visit "http://fpga.mty.itesm.mx" for more info.

--

-- 2003-2004. V1.0

--

LIBRARY ieee;

USE ieee.std_logic_1164.all;

USE ieee.std_logic_arith.all;

ENTITY FPadd_normalize IS

   PORT(

      EXP_in  : IN     std_logic_vector (7 DOWNTO 0);

      SIG_in  : IN     std_logic_vector (27 DOWNTO 0);

      EXP_out : OUT    std_logic_vector (7 DOWNTO 0);

      SIG_out : OUT    std_logic_vector (27 DOWNTO 0);

      zero    : OUT    std_logic

   );

-- Declarations

END FPadd_normalize ;

--

-- VHDL Architecture work.FPadd_normalize.struct

--

-- Created by

-- Guillermo Marcus, gmarcus@ieee.org

-- using Mentor Graphics FPGA Advantage tools.

--

-- Visit "http://fpga.mty.itesm.mx" for more info.

--

-- Copyright 2003-2004. V1.0

--

LIBRARY ieee;

USE ieee.std_logic_1164.all;

USE ieee.std_logic_arith.all;

USE ieee.std_logic_unsigned.all;

ARCHITECTURE struct OF FPadd_normalize IS

   -- Architecture declarations

   -- Internal signal declarations

   SIGNAL EXP_lshift : std_logic_vector(7 DOWNTO 0);

   SIGNAL EXP_rshift : std_logic_vector(7 DOWNTO 0);

   SIGNAL SIG_lshift : std_logic_vector(27 DOWNTO 0);

   SIGNAL SIG_rshift : std_logic_vector(27 DOWNTO 0);

   SIGNAL add_in     : std_logic_vector(7 DOWNTO 0);

   SIGNAL cin        : std_logic;

   SIGNAL count      : std_logic_vector(4 DOWNTO 0);

   SIGNAL isDN       : std_logic;

   SIGNAL shift_RL   : std_logic;

   SIGNAL word       : std_logic_vector(26 DOWNTO 0);

   SIGNAL zero_int   : std_logic;

   SIGNAL denormal   : std_logic;

        SIGNAL lshift_cnt : std_logic_vector(4 DOWNTO 0);

   -- Component Declarations

   COMPONENT FPlzc

   PORT (

      word  : IN     std_logic_vector (26 DOWNTO 0);

      zero  : OUT    std_logic ;

      count : OUT    std_logic_vector (4 DOWNTO 0)

   );

   END COMPONENT;

   -- Optional embedded configurations

   -- pragma synthesis_off

   FOR ALL : FPlzc USE ENTITY work.FPlzc;

   -- pragma synthesis_on

BEGIN

   -- Architecture concurrent statements

   -- HDL Embedded Text Block 1 eb1

   -- eb1 1                                        

   SIG_rshift <= '0' & SIG_in(27 DOWNTO 2) & (SIG_in(1) AND SIG_in(0));

   -- HDL Embedded Text Block 2 eb2

   -- eb2 2                    

   add_in <= "000" & count;

        -- limit the count to the exponent value

        PROCESS(count,EXP_in)

        BEGIN

                IF (signed(count) > signed(EXP_in)) THEN

                        lshift_cnt <= EXP_in(4 downto 0)-1;

                        denormal <= '1';

                ELSE

                        lshift_cnt <= count;

                        denormal <= '0';

                END IF;

        END PROCESS;

   -- HDL Embedded Text Block 3 eb3

   -- eb3 3

   PROCESS( isDN, shift_RL, EXP_lshift, EXP_rshift, EXP_in, SIG_lshift, SIG_rshift, SIG_in, denormal)

   BEGIN

   IF (isDN='1') THEN

      EXP_out <= X"00";

      SIG_out <= SIG_in;

   ELSE

      IF (shift_RL='1') THEN

         -- Shift Right

         IF (SIG_in(27)='1') THEN

            EXP_out <= EXP_rshift;

            SIG_out <= SIG_rshift;

         ELSE

            EXP_out <= EXP_in;

            SIG_out <= SIG_in;

         END IF;

      ELSE

         -- Shift Left

                        IF (denormal='1') THEN

                                EXP_out <= (OTHERS => '0');

                                SIG_out <= SIG_lshift;

                        ELSE

                                EXP_out <= EXP_lshift;

                                SIG_out <= SIG_lshift;

                        END IF;

      END IF;

   END IF;

   END PROCESS;

   -- HDL Embedded Text Block 4 eb4

   -- eb4 4

   zero <= zero_int AND NOT SIG_in(27);

   -- HDL Embedded Text Block 5 eb5

   -- eb5 5

   word <= SIG_in(26 DOWNTO 0);

   -- HDL Embedded Text Block 6 eb6

   -- eb6 6

   PROCESS(SIG_in,EXP_in)

   BEGIN

      IF (SIG_in(27)='0' AND SIG_in(26)='0' AND (EXP_in=X"01")) THEN

         isDN <= '1';

         shift_RL <= '0';

      ELSIF (SIG_in(27)='0' AND SIG_in(26)='0' AND (EXP_in/=X"00")) THEN

         isDN <= '0';

         shift_RL <= '0';

      ELSE

         isDN <= '0';

         shift_RL <= '1';

      END IF;

   END PROCESS;

   -- ModuleWare code(v1.1) for instance 'I3' of 'gnd'

   cin <= '0';

   -- ModuleWare code(v1.1) for instance 'I4' of 'inc'

   I4combo: PROCESS (EXP_in)

   VARIABLE t0 : std_logic_vector(8 DOWNTO 0);

   VARIABLE sum : signed(8 DOWNTO 0);

   VARIABLE din_l : std_logic_vector(7 DOWNTO 0);

   BEGIN

      din_l := EXP_in;

      t0 := din_l(7) & din_l;

      sum := (signed(t0) + '1');

      EXP_rshift <= conv_std_logic_vector(sum(7 DOWNTO 0),8);

   END PROCESS I4combo;

   -- ModuleWare code(v1.1) for instance 'I1' of 'lshift'

   I1combo : PROCESS (SIG_in, lshift_cnt)

   VARIABLE stemp : std_logic_vector (4 DOWNTO 0);

   VARIABLE dtemp : std_logic_vector (27 DOWNTO 0);

   VARIABLE temp : std_logic_vector (27 DOWNTO 0);

   BEGIN

      temp := (OTHERS=> 'X');

      stemp := lshift_cnt;

      temp := SIG_in;

      FOR i IN 4 DOWNTO 0 LOOP

         IF (i < 5) THEN

            IF (stemp(i) = '1' OR stemp(i) = 'H') THEN

               dtemp := (OTHERS => '0');

               dtemp(27 DOWNTO 2**i) := temp(27 - 2**i DOWNTO 0);

            ELSIF (stemp(i) = '0' OR stemp(i) = 'L') THEN

               dtemp := temp;

            ELSE

               dtemp := (OTHERS => 'X');

            END IF;

         ELSE

            IF (stemp(i) = '1' OR stemp(i) = 'H') THEN

               dtemp := (OTHERS => '0');

            ELSIF (stemp(i) = '0' OR stemp(i) = 'L') THEN

               dtemp := temp;

            ELSE

               dtemp := (OTHERS => 'X');

            END IF;

         END IF;

         temp := dtemp;

      END LOOP;

      SIG_lshift <= dtemp;

   END PROCESS I1combo;

   -- ModuleWare code(v1.1) for instance 'I2' of 'sub'

   I2combo: PROCESS (EXP_in, add_in, cin)

   VARIABLE mw_I2t0 : std_logic_vector(8 DOWNTO 0);

   VARIABLE mw_I2t1 : std_logic_vector(8 DOWNTO 0);

   VARIABLE diff : signed(8 DOWNTO 0);

   VARIABLE borrow : std_logic;

   BEGIN

      mw_I2t0 := EXP_in(7) & EXP_in;

      mw_I2t1 := add_in(7) & add_in;

      borrow := cin;

      diff := signed(mw_I2t0) - signed(mw_I2t1) - borrow;

      EXP_lshift <= conv_std_logic_vector(diff(7 DOWNTO 0),8);

   END PROCESS I2combo;

   -- Instance port mappings.

   I0 : FPlzc

      PORT MAP (

         word  => word,

         zero  => zero_int,

         count => count

      );

END struct;