-------------------------------------------------------------------------------
--
-- AXI4-AXI4 Stream FIFO Core - AXI4-AXI4 Stream FIFO Package
--
-------------------------------------------------------------------------------
-- (c) Copyright 2006 - 2013 Xilinx, Inc. All rights reserved.
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-------------------------------------------------------------------------------
--
-- Filename: axi_fifo_mm_s_pkg.vhd
--
-- Author: Xilinx
--
-- Description:
--   This file is the package file of the AXI4-AXI4 Stream FIFO Core. It
--   contains all function declarations and bodies that are used in all
--   AXI4-AXI4 Stream FIFO Core modules and submodules.
--
-------------------------------------------------------------------------------
-- Structure:
--     axi_fifo_mm_s_pkg
--
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
-- LIBRARY DECLARATIONS
-------------------------------------------------------------------------------

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE ieee.std_logic_arith.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;

PACKAGE axi_fifo_mm_s_pkg IS

  CONSTANT ZERO                 : std_logic := '0';
  CONSTANT FLOP_DELAY           : time := 100 PS;
  CONSTANT TDFD_OFFSET          : std_logic_vector(31 downto 0) := X"00000000";
  CONSTANT RDFD_OFFSET          : std_logic_vector(31 downto 0) := X"00001000";

  -----------------------------------------------------------------------------
  -- FUNCTION DECLARATIONS
  -----------------------------------------------------------------------------

  FUNCTION if_then_else (
    condition : BOOLEAN;
    true_case : INTEGER;
    false_case : INTEGER)
    RETURN INTEGER;

  FUNCTION divroundup (
    data_value : INTEGER;
    divisor : INTEGER)
    RETURN INTEGER;

  FUNCTION log2roundup (
    data_value : INTEGER)
    RETURN INTEGER;

  FUNCTION count_ones (
      indata  : std_logic_vector;
      indata_size : integer)
    RETURN integer;

END axi_fifo_mm_s_pkg;

-------------------------------------------------------------------------------
-- PACKAGE BODY
-------------------------------------------------------------------------------
PACKAGE BODY axi_fifo_mm_s_pkg IS

  ------------------------------------------------------------------------------
  -- FUNCTION: if_then_else
  -- This function is used to implement an IF..THEN when such a statement is not
  --  allowed.
  ------------------------------------------------------------------------------
  FUNCTION if_then_else (
    condition : BOOLEAN;
    true_case : INTEGER;
    false_case : INTEGER)
  RETURN INTEGER IS
    VARIABLE retval : INTEGER := 0;
  BEGIN
    IF NOT condition THEN
      retval:=false_case;
    ELSE
      retval:=true_case;
    END IF;
    RETURN retval;
  END if_then_else;

 -----------------------------------------------------------------------------
  -- FUNCTION : divroundup
  -- Returns the ceiling value of the division
  -- Data_value - the quantity to be divided, dividend
  -- Divisor - the value to divide the data_value by
  -----------------------------------------------------------------------------
  FUNCTION divroundup (
    data_value : INTEGER;
    divisor : INTEGER)
  RETURN INTEGER IS
    VARIABLE div                   : INTEGER;
  BEGIN
    div   := data_value/divisor;
    IF ( (data_value MOD divisor) /= 0) THEN
      div := div+1;
    END IF;
    RETURN div;
  END divroundup;

  -----------------------------------------------------------------------------
  -- FUNCTION : log2roundup
  -----------------------------------------------------------------------------
  FUNCTION log2roundup (
    data_value : INTEGER)
  RETURN INTEGER IS

    VARIABLE width       : INTEGER := 0;
    VARIABLE cnt         : INTEGER := 1;
    CONSTANT lower_limit : INTEGER := 1;
    CONSTANT upper_limit : INTEGER := 8;

  BEGIN
    IF (data_value <= 1) THEN
      width   := 0;
    ELSE
      WHILE (cnt < data_value) LOOP
        width := width + 1;
        cnt   := cnt *2;
      END LOOP;
    END IF;

    RETURN width;
  END log2roundup;

  --------------------------------------------------------
  -- FUNCION : count_ones_nbit
  -- Returns the binary encoded value of number of ones
  --------------------------------------------------------
  FUNCTION count_ones (
      indata  : std_logic_vector;
      indata_size : integer)
    RETURN integer IS
      VARIABLE tmp : integer := 0;
    BEGIN
       FOR i IN indata_size-1 DOWNTO 0 LOOP
         IF indata(i) = '0' THEN 
	   EXIT; 
	 END IF;
	 tmp := tmp + 1;
       end loop;
      RETURN tmp;
    END count_ones; 
END axi_fifo_mm_s_pkg;