----------------------------------------------------------------------------------
-- Company:Zuritronic 
-- Engineer:a.Kurka 
--
-- Create Date:   06.05.2021 by a.kurka
-- Design Name: 		AS21
-- Module Name:    cosFP - Behavioral 
--  modified : 09.05.2021 by a.kurka
-- cos = func_C(ainp^2); -- für den Bereich [-PI/2,PI/2]
----------------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;


entity CosFP is
	port(	nrst			: in std_logic;
			clk 			: in std_logic;
			cecos     : in std_logic;-- startimpuls afkt
			ainp			:in std_logic_vector(31 downto 0);-- input afkt FP  format
			cos			:OUT std_logic_vector(31 downto 0)-- output afkt FP  format
			);
end CosFP;

architecture Behavioral of CosFP is
--====================================================
COMPONENT func_C is
	port(	nrst			: in std_logic;
			clk 			: in std_logic;
			cefktC     : in std_logic;-- startimpuls fkt_C
			Xinp			:in std_logic_vector(31 downto 0);-- input afkt FP  format
			aout		:OUT std_logic_vector(31 downto 0)-- output afkt FP  format
			);
END COMPONENT;
-----------------------------------------
COMPONENT mulFP IS
	port (
	a: IN std_logic_VECTOR(31 downto 0);
	b: IN std_logic_VECTOR(31 downto 0);
	clk: IN std_logic;
	ce: IN std_logic;
	result: OUT std_logic_VECTOR(31 downto 0));
END COMPONENT;

--========================================================
CONSTANT PIdiv2 	:std_logic_vector(31 DOWNTO 0):=X"3FC90FDB";--1.57079632679 PI/2 in FP Format

--==================================================================
SIGNAL ce1	 	:std_logic:= '0';
SIGNAL ce2	 	:std_logic:= '0';
SIGNAL ain  	:std_logic_VECTOR(31 downto 0):=X"00000000";
--==================================================================
begin
--------------------------------------------------------------
pcos :PROCESS (clk)
VARIABLE cntrclk : INTEGER RANGE 0 TO 127:= 0;
variable state :INTEGER RANGE 0 TO 7:= 0;
BEGIN
	IF rising_edge(clk) THEN
		IF nrst = '0' THEN
			state := 0;
			cntrclk := 0;
			--(OTHERS => '0');
		ELSE
			CASE state IS
				WHEN 0 =>
					IF cecos = '1' THEN
						ce1 <= '1';-- start für 1-x, x`2, ComP0.5
						state := 1;
					ELSE
						state := 0;
					END IF;
				WHEN 1 => --- Ausführen ain :=ainp^2
						ce1 <= '0';
						ce2 <= '1';-- start für fkt_c
						cntrclk := 11;
						state := 2;
				WHEN 2 => ---- mul2mX,2powX fertig
					IF cntrclk = 0 THEN
						state := 0;--warten auf nächste Start
					ELSE
						ce2 <= '0';
						cntrclk := cntrclk -1;
						state := 2;
					END IF;
				WHEN OTHERS =>
					state := 0;
			END CASE;
		END IF; -- if nrst/else
  END IF; -- clk
END PROCESS;--end pacos

--=======Implementation==================================
 
cmulX : mulFP port map(a=>ainp,b=>ainp,clk=>clk,ce=>ce1,result=>ain);
cfuncC: func_c port map(nrst=>nrst,clk=>clk,cefktC=>ce2,Xinp=>ain,aout=>cos);

---------------------------------------------------	
end Behavioral;