Subversion Repositories copyblaze

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-- Company: 

--

-- File: cp_Flags.vhd

--

-- Description:

--      projet copyblaze

--      Flags ZERO & CARRY management

--

-- File history:

-- v1.0: 10/10/11: Creation

--

-- Targeted device: ProAsic A3P250 VQFP100

-- Author: AbdAllah Meziti

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library ieee;

use ieee.std_logic_1164.all;

use ieee.numeric_std.all;

use     work.Usefull_Pkg.all;           -- Usefull Package

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-- Entity: cp_Flags

--

-- Description:

--      

--      REMARQUE:

--

--      

-- History:

-- 10/10/11 AM: Creation

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

-- xx/xx/xx AM: 

--                              

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entity cp_Flags is

        port (

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

        -- Signaux Systeme

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

                Clk_i                           : in std_ulogic;        --      signal d'horloge générale

                Rst_i_n                         : in std_ulogic;        --      signal de reset générale

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

        -- Signaux Fonctionels

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

                Z_i                                     : in std_ulogic;

                C_i                                     : in std_ulogic;

                Z_o                                     : out std_ulogic;

                C_o                                     : out std_ulogic;

                Push_i                          : in std_ulogic;

                Pop_i                           : in std_ulogic;

                Write_i                         : in std_ulogic

        );

end cp_Flags;

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-- Architecture: RTL

-- of entity : cp_Flags

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

architecture rtl of cp_Flags is

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

        -- Définition des fonctions

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

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

        -- Définition des constantes

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

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

        -- Définition des signaux interne

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

        signal          iZ              : std_ulogic;   -- flag

        signal          iC              : std_ulogic;   -- flag

        signal          iZs             : std_ulogic;   -- Shadow flag

        signal          iCs             : std_ulogic;   -- Shadow flag

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

        -- Déclaration des composants

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

begin

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

        -- Process : Flags_Proc

        -- Description: Flags Management

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

        Flags_Proc : process(Rst_i_n, Clk_i)

        begin

                if ( Rst_i_n = '0' ) then

                        iZ      <=      '0';

                        iC      <=      '0';

                elsif ( rising_edge(Clk_i) ) then

                        if ( Write_i = '1' ) then

                                iZ      <=      Z_i;

                                iC      <=      C_i;

                        elsif ( Pop_i = '1' ) then

                                iZ      <=      iZs;

                                iC      <=      iCs;

                        end if;

                end if;

        end process Flags_Proc;

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

        -- Process : ShadowFlags_Proc

        -- Description: Shadow Flags Management

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

        ShadowFlags_Proc : process(Rst_i_n, Clk_i)

        begin

                if ( Rst_i_n = '0' ) then

                        iZs     <=      '0';

                        iCs     <=      '0';

                elsif ( rising_edge(Clk_i) ) then

                        if ( Push_i = '1' ) then

                                iZs     <=      iZ;

                                iCs     <=      iC;

                        end if;

                end if;

        end process ShadowFlags_Proc;

        Z_o             <=      iZ;

        C_o             <=      iC;

end rtl;