Subversion Repositories graphicsaccelerator

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

use IEEE.numeric_std.all;

use IEEE.std_logic_unsigned.all;

entity Pointer is

         Generic (initX : STD_LOGIC_VECTOR (9 downto 0);

                                 initY : STD_LOGIC_VECTOR (8 downto 0));

    Port ( MoveUp : in  STD_LOGIC;

           MoveDown : in  STD_LOGIC;

                          MoveLeft : in  STD_LOGIC;

                          MoveRight : in  STD_LOGIC;

           Move : in  STD_LOGIC;

           Clk : in  STD_LOGIC;

           Here : out  STD_LOGIC;

                          X : out  STD_LOGIC_VECTOR (9 downto 0);

                          Y : out  STD_LOGIC_VECTOR (8 downto 0);

           syncX : in  STD_LOGIC_VECTOR (9 downto 0);

           syncY : in  STD_LOGIC_VECTOR (8 downto 0));

end Pointer;

architecture Behavioral of Pointer is

signal rX : STD_LOGIC_VECTOR (9 downto 0) := initX;

signal rY : STD_LOGIC_VECTOR (8 downto 0) := initY;

begin

Here <= '1' when syncX(9 downto 3)=rX(9 downto 3) and

                                          syncY(8 downto 3)=rY(8 downto 3) else '0';

X <= rX;

Y <= rY;

process (Clk) begin

        if (rising_edge(Clk)) then

                if (Move = '1') then

                        if (MoveLeft = '1' and MoveRight = '0') then

                                if not (rX = "0000000000") then

                                        rX <= rX - 1;

                                end if;

                        elsif (MoveLeft = '0' and MoveRight = '1') then

                                if not (rX = "1001111111") then

                                        rX <= rX + 1;

                                end if;

                        end if;

                        if (MoveUp = '1' and MoveDown = '0') then

                                if not (rY = "000000000") then

                                        rY <= rY - 1;

                                end if;

                        elsif (MoveUp = '0' and MoveDown = '1') then

                                if not (rY = "111011111") then

                                        rY <= rY + 1;

                                end if;

                        end if;

                end if;

        end if;

end process;

end Behavioral;