Subversion Repositories cpu65c02_true_cycle

LIBRARY ieee;

USE ieee.std_logic_1164.all;

USE ieee.std_logic_arith.all;

entity reg_sp is

   port(

      adr_low_i   : in     std_logic_vector (7 downto 0);

      clk_clk_i   : in     std_logic;

      ld_low_i    : in     std_logic;

      ld_sp_i     : in     std_logic;

      rst_rst_n_i : in     std_logic;

      sel_sp_as_i : in     std_logic;

      sel_sp_in_i : in     std_logic;

      adr_sp_o    : out    std_logic_vector (15 downto 0)

   );

-- Declarations

end reg_sp ;

-- (C) 2008 - 2021 Jens Gutschmidt

-- (email: opencores@vivare-services.com)

-- 

-- Versions:

-- Revision 1.7  2013/07/21 11:11:00  jens

-- - Changing the title block and internal revision history

-- 

-- Revision 1.6  2009/01/04 10:20:47  eda

-- Changes for cosmetic issues only

-- 

-- Revision 1.5  2009/01/04 09:23:10  eda

-- - Delete unused nets and blocks (same as R6502_TC)

-- - Rename blocks

-- 

-- Revision 1.4  2009/01/03 16:53:02  eda

-- - Unused nets and blocks deleted

-- - Renamed blocks

-- 

-- Revision 1.3  2009/01/03 16:42:02  eda

-- - Unused nets and blocks deleted

-- - Renamed blocks

-- 

-- Revision 1.2  2008/12/31 19:31:24  eda

-- Production Release

--  

-- 

--

-- r65c02_tc.reg_sp.struct

--

-- Date:    06.01.2021

-- Time:    22:58:19

-- By:        VIVARE GmbH, Switzerland

--

-- COPYRIGHT (C) 2008 - 2021 by Jens Gutschmidt

-- 

-- This program 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 any later version.

-- 

-- This program 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 program.  If not, see <http://www.gnu.org/licenses/>.

-- 

-- 

LIBRARY ieee;

USE ieee.std_logic_1164.all;

USE ieee.std_logic_arith.all;

architecture struct of reg_sp is

   -- Architecture declarations

   -- Internal signal declarations

   signal adr_sp_low_o_i  : std_logic_vector(7 downto 0);

   signal load_o_i        : std_logic;

   signal result_low1_o_i : std_logic_vector(7 downto 0);

   signal result_low_o_i  : std_logic_vector(7 downto 0);

   signal sp_as_n_o_i     : std_logic;

   signal val_one         : std_logic_vector(7 downto 0);

   -- Implicit buffer signal declarations

   signal adr_sp_o_internal : std_logic_vector (15 downto 0);

   -- ModuleWare signal declarations(v1.12) for instance 'U_0' of 'adff'

   signal mw_U_0reg_cval : std_logic_vector(7 downto 0);

begin

   -- ModuleWare code(v1.12) for instance 'U_11' of 'addsub'

   u_11combo_proc: process (adr_sp_low_o_i, val_one, sp_as_n_o_i)

   variable temp_din0 : std_logic_vector(8 downto 0);

   variable temp_din1 : std_logic_vector(8 downto 0);

   variable temp_sum : unsigned(8 downto 0);

   variable temp_carry : std_logic;

   begin

      temp_din0 := '0' & adr_sp_low_o_i;

      temp_din1 := '0' & val_one;

      temp_carry := '0';

      if (sp_as_n_o_i = '1') then

         temp_sum := unsigned(temp_din0) + unsigned(temp_din1) + temp_carry;

      else

         temp_sum := unsigned(temp_din0) - unsigned(temp_din1) - temp_carry;

      end if;

      result_low_o_i <= conv_std_logic_vector(temp_sum(7 downto 0),8);

   end process u_11combo_proc;

   -- ModuleWare code(v1.12) for instance 'U_0' of 'adff'

   adr_sp_o_internal(7 DOWNTO 0) <= mw_U_0reg_cval;

   u_0seq_proc: process (clk_clk_i, rst_rst_n_i)

   begin

      if (rst_rst_n_i = '0') then

         mw_U_0reg_cval <= "00000000";

      elsif (clk_clk_i'event and clk_clk_i='1') then

         if (load_o_i = '1') then

            mw_U_0reg_cval <= result_low1_o_i;

         end if;

      end if;

   end process u_0seq_proc;

   -- ModuleWare code(v1.12) for instance 'U_6' of 'and'

   load_o_i <= ld_sp_i and ld_low_i;

   -- ModuleWare code(v1.12) for instance 'U_3' of 'buff'

   adr_sp_o_internal(15 DOWNTO 8) <= val_one;

   -- ModuleWare code(v1.12) for instance 'U_4' of 'constval'

   val_one <= "00000001";

   -- ModuleWare code(v1.12) for instance 'U_2' of 'inv'

   sp_as_n_o_i <= not(sel_sp_as_i);

   -- ModuleWare code(v1.12) for instance 'U_8' of 'mux'

   u_8combo_proc: process(result_low_o_i, adr_low_i, sel_sp_in_i)

   begin

      case sel_sp_in_i is

      when '0' => result_low1_o_i <= result_low_o_i;

      when '1' => result_low1_o_i <= adr_low_i;

      when others => result_low1_o_i <= (others => 'X');

      end case;

   end process u_8combo_proc;

   -- ModuleWare code(v1.12) for instance 'U_10' of 'tap'

   adr_sp_low_o_i <= adr_sp_o_internal(7 downto 0);

   -- Instance port mappings.

   -- Implicit buffered output assignments

   adr_sp_o <= adr_sp_o_internal;

end struct;