library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.numeric_std.all;

package cic_utils is
   -- parametros de diseño del filtro CIC ----------------------------------------
	constant MANTISSA_BITS : integer := 24;
	constant NUMBER_BITS : integer := 32; -- incluye bit de signo
	constant FIXWIDTH    : integer := NUMBER_BITS + MANTISSA_BITS;
	constant STAGES      : integer := 5; -- orden del filtro CIC (numero de etapas)
	
	-- no modificar ---------------------------------------------------------------
	subtype fixpoint is std_logic_vector(FIXWIDTH-1 downto 0);
	function "*"(a: std_logic_vector ; b: std_logic_vector) return std_logic_vector;
	function "/"(a: std_logic_vector ; b: std_logic_vector) return std_logic_vector;
	function "+"(a: std_logic_vector ; b: std_logic_vector) return std_logic_vector;
	function "-"(a: std_logic_vector ; b: std_logic_vector) return std_logic_vector;
	function to_fix(a: integer) return std_logic_vector;
	constant MAX_M2_DEC : integer := 19;
	constant ONE: integer := 2**MANTISSA_BITS;
	
end cic_utils;




package body cic_utils is
-- operaciones aritmeticas de punto fijo
	function "*" ( a: std_logic_vector ; b: std_logic_vector)
		return std_logic_vector is
	variable ret : std_logic_vector(2*FIXWIDTH-1 downto 0);
	begin
		ret := std_logic_vector(signed(a)*signed(b));
		return ret(a'length+MANTISSA_BITS-1 downto MANTISSA_BITS);
	end "*";


	function "/" (a: std_logic_vector ; b: std_logic_vector)
		return std_logic_vector is
	variable ret : std_logic_vector(a'length+MANTISSA_BITS-1 downto 0);
	variable tmp : std_logic_vector(a'length+MANTISSA_BITS-1 downto 0):=(others=>'0');
	begin
		for i in 0 to a'length-1 loop
			tmp(i+MANTISSA_BITS	) := a(i);
		end loop;
		ret := std_logic_vector(signed(tmp)/signed(b));
		return ret(a'length-1 downto 0);
	end "/";
			 
			 
	function "+" (a: std_logic_vector ; b: std_logic_vector)
		return std_logic_vector is
	variable ret : std_logic_vector(a'length-1 downto 0);
	begin
		ret := std_logic_vector(signed(a)+signed(b));
		return ret;
	end "+";
	
	
	function "-" (a: std_logic_vector ; b: std_logic_vector)
		return std_logic_vector is
	variable ret : std_logic_vector(a'length-1 downto 0);
	begin
		ret := std_logic_vector(signed(a)-signed(b));
		return ret;
	end "-";

-- 
	
	function to_fix(a: integer)
		return std_logic_vector is
	variable ret : std_logic_vector(FIXWIDTH-1 downto 0);
	begin
		ret := std_logic_vector(to_signed(a,FIXWIDTH));
		return ret;
	end to_fix;
	
end cic_utils;