pfb_5n_vhdl/utils/used_functions_pkg.vhd

LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
USE ieee.std_logic_signed.ALL;
USE ieee.numeric_std.ALL;

PACKAGE used_functions_pkg IS

  FUNCTION log2_sup_integer (number : natural) RETURN natural;
  FUNCTION log2_inf_integer (number : natural) RETURN natural;


END PACKAGE;

PACKAGE BODY used_functions_pkg IS

 --functions
  FUNCTION log2_sup_integer (number : natural) RETURN natural IS
    VARIABLE result : natural;
  BEGIN

    IF(number <= 1) THEN
      result := 0;
    ELSIF(number = 2) THEN
      result := 1;
    ELSIF(number > 2 AND number <= 4) THEN
      result := 2;
    ELSIF(number > 4 AND number <= 8) THEN
      result := 3;
    ELSIF(number > 8 AND number <= 16) THEN
      result := 4;
    ELSIF(number > 16 AND number <= 32) THEN
      result := 5;
    ELSIF(number > 32 AND number <= 64) THEN
      result := 6;
    ELSIF(number > 64 AND number <= 128) THEN
      result := 7;
    ELSIF(number > 128 AND number <= 256) THEN
      result := 8;
    ELSIF(number > 256 AND number <= 512) THEN
      result := 9;
    ELSIF(number > 512 AND number <= 1024) THEN
      result := 10;
    ELSIF(number > 1024 AND number <= 2048) THEN
      result := 11;
    ELSIF(number > 2048 AND number <= 4096) THEN
      result := 12;
    ELSIF(number > 4096 AND number <= 8192) THEN
      result := 13;
    ELSIF(number > 8192 AND number <= 16384) THEN
      result := 14;
    ELSIF(number > 16384 AND number <= 32768) THEN
      result := 15;
    END IF;
    RETURN result;
  END FUNCTION;

  FUNCTION log2_inf_integer (number : natural) RETURN natural IS
    VARIABLE result : natural;
  BEGIN

    IF(number < 2) THEN
      result := 0;
    ELSIF(number >= 2 AND number < 4) THEN
      result := 1;
    ELSIF(number >= 4 AND number < 8) THEN
      result := 2;
    ELSIF(number >= 8 AND number < 16) THEN
      result := 3;
    ELSIF(number >= 16 AND number < 32) THEN
      result := 4;
    ELSIF(number >= 32 AND number < 64) THEN
      result := 5;
    ELSIF(number >= 64 AND number < 128) THEN
      result := 6;
    ELSIF(number >= 128 AND number < 256) THEN
      result := 7;
    ELSIF(number >= 256 AND number < 512) THEN
      result := 8;
    ELSIF(number >= 512 AND number < 1024) THEN
      result := 9;
    ELSIF(number >= 1024 AND number < 2048) THEN
      result := 10;
    ELSIF(number >= 2048 AND number < 4096) THEN
      Result := 11;
    ELSIF(Number >= 4096 AND number < 8192) THEN
      result := 12;
    ELSIF(number >= 8192 AND number < 16384) THEN
      result := 13;
    ELSIF(number >= 16384 AND number < 32768) THEN
      result := 14;
    END IF;
    RETURN result;
  END FUNCTION;

END PACKAGE BODY used_functions_pkg;