The code written below is according to the Image attached of an I2C 
master controller, i am having difficulties to make the Vhdl file for 
every block instead of all in a single file.
thank you.

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;

entity i2c_master_registers is
  port (
        wb_clk_i : in  std_logic;
        rst_i    : in  std_logic;
        wb_rst_i : in  std_logic;
        wb_dat_i : in  std_logic_vector(7 downto 0);
        wb_adr_i : in  std_logic_vector(2 downto 0);
        wb_wacc  : in  std_logic;
        i2c_al   : in  std_logic;
        i2c_busy : in  std_logic;
        done     : in  std_logic;
        irxack   : in  std_logic;
        prer     : out std_logic_vector(15 downto 0);  -- clock prescale 
register
        ctr      : out std_logic_vector(7 downto 0);  -- control 
register
        txr      : out std_logic_vector(7 downto 0);  -- transmit 
register
        cr       : out std_logic_vector(7 downto 0);  -- command 
register
        sr       : out std_logic_vector(7 downto 0)    -- status 
register
        );
end;

architecture arch of i2c_master_registers is


signal ctr_int : std_logic_vector(7 downto 0);
signal cr_int : std_logic_vector(7 downto 0);

signal al : std_logic;      -- status register arbitration lost bit
signal rxack : std_logic;    -- received aknowledge from slave
signal tip : std_logic;      -- transfer in progress
signal irq_flag : std_logic;  -- interrupt pending flag

begin

-- generate prescale regisres, control registers, and transmit register
process(wb_clk_i,rst_i)
begin
  if (rst_i = '0') then
    prer <= (others => '1');
    ctr_int <= (others => '0');
    txr <= (others => '0');
  elsif rising_edge(wb_clk_i) then
    if (wb_rst_i = '1') then
      prer <= (others => '1');
      ctr_int <= (others => '0');
      txr <= (others => '0');
    elsif (wb_wacc = '1') then
      case (wb_adr_i) is
        when "000" => prer(7 downto 0)  <= wb_dat_i;
        when "001" => prer(15 downto 8)  <= wb_dat_i;
        when "010" => ctr_int      <= wb_dat_i;
        when "011" => txr        <= wb_dat_i;
        when others => NULL;
      end case;
    end if;
  end if;
end process;

ctr <= ctr_int;

-- generate command register (special case)
process(wb_clk_i,rst_i)
begin
  if (rst_i = '0') then
    cr_int <= (others => '0');
  elsif rising_edge(wb_clk_i) then
    if (wb_rst_i = '1') then
      cr_int <= (others => '0');
    elsif (wb_wacc = '1') then
      if ((ctr_int(7) = '1') AND (wb_adr_i = "100")) then
        cr_int <= wb_dat_i;
      end if;
    else
      if ((done = '1') OR (i2c_al = '1')) then
        cr_int(7 downto 4) <= "0000";  -- clear command b
      end if;              -- or when aribitr
      cr_int(2 downto 1) <= "00";      -- reserved bits
      cr_int(0) <= '0';          -- clear IRQ_ACK b
    end if;
  end if;
end process;

cr <= cr_int;

-- generate status register block + interrupt request signal
-- each output will be assigned to corresponding sr register locations 
on top level
process(wb_clk_i,rst_i)
begin
  if (rst_i = '0') then
    al       <= '0';
    rxack     <= '0';
    tip     <= '0';
    irq_flag  <= '0';
  elsif rising_edge(wb_clk_i) then
    if (wb_rst_i = '1') then
      al       <= '0';
      rxack     <= '0';
      tip     <= '0';
      irq_flag  <= '0';
    else
      al      <= i2c_al OR (al AND NOT(cr_int(7)));
      rxack    <= irxack;
      tip      <= (cr_int(5) OR cr_int(4));
      irq_flag  <= (done OR i2c_al OR irq_flag) AND NOT(cr_int(0)); -- 
interrupt request flag is always generated
    end if;
  end if;
end process;

sr(7)       <= rxack;
sr(6)      <= i2c_busy;
sr(5)      <= al;
sr(4 downto 2)  <= "000"; -- reserved
sr(1)      <= tip;
sr(0)      <= irq_flag;


end arch;