-------------------------------------------------------------  File: post.vhd                                       ----  created : July 09,2001 15:00                         ----  mail to khaer@opencores.org                          -------------------------------------------------------------library IEEE;use IEEE.std_logic_1164.all;use IEEE.STD_LOGIC_ARITH.all;use IEEE.STD_LOGIC_SIGNED.all;entity post_20b15i is	port (		clk           : in  STD_LOGIC;		scaled_radius : in  STD_LOGIC_VECTOR (19 downto 0);		input_angle   : in  STD_LOGIC_VECTOR (18 downto 0);		angle         : out STD_LOGIC_VECTOR (19 downto 0);		octant        : in  STD_LOGIC_VECTOR (2 downto 0);		radius        : out STD_LOGIC_VECTOR (19 downto 0)		);end post_20b15i;architecture post_20b15i of post_20b15i is	signal tmp1,tmp2,tmp3,tmp4 : std_logic_vector (20 downto 0);   signal in_angl,ang3        : std_logic_vector (19 downto 0);signal ang2,ang1           : std_logic_vector (18 downto 0);       signal o0,o1               : std_logic_vector (2 downto 0);		signal ang                 : std_logic_vector (19 downto 0); begin		process(clk)		variable ang : std_logic_vector (19 downto 0); 		variable pi2 : std_logic_vector (19 downto 0); 		variable pi  : std_logic_vector (19 downto 0); 		variable acc : std_logic_vector (20 downto 0);         		variable add : std_logic_vector (20 downto 0);         			begin 		if clk'event and clk='1' then  			o0   <= octant;			o1   <= o0;						ang1 <= input_angle;			ang2 <= ang1;					        ang  := o1(2) & o1(1) & "000000000000000000";		        if o1(0) = '0' then		           angle <= ang + sxt(ang2, 20);		        else		           angle <= ang - sxt(ang2, 20);		        end if;   		           -- approximation of 0,858785337-- 1-((1/8+1/64)+(1/8+1/64)/256+(1/8+1/64)/4096)=0,858791351-- this is an 0,0000060147 error	 						acc    := (scaled_radius & '0');			add    := "000" & scaled_radius(19 downto 2);			tmp1   <= add+("000000" & scaled_radius(19 downto 5));			tmp2   <= acc;			tmp3   <= tmp1+("00000000" & tmp1(20 downto 8));			tmp4   <= tmp2-("000000000000" & tmp1(20 downto 12));			acc    := tmp4-tmp3;			radius <= acc(20 downto 1);		end if;	end process;	end post_20b15i;