-- Fichier             :    median.vhd                       
-- Societe             :    ENSERB                        
-- Auteur              :    P.Nouel
-- Date de creation    :    Octobre 99
-- Contenu             :    Filtre median 
-- Synthetisable ?     :    Non
--------------------------------------------------------------------------------
LIBRARY IEEE; 
USE IEEE.STD_LOGIC_1164.ALL;
USE ieee.numeric_std.ALL;

USE work.paq_tri.ALL;

ARCHITECTURE median OF filtre IS 
  SIGNAL p1, p2 ,p3, p4, p5, p6, p7, p8, p9 : natural RANGE 0 TO 255;
  SIGNAL autorise : std_ulogic;-- pour entree donnees
  SIGNAL p123, m123, g123, calcul : natural RANGE 0 TO 255;
  SIGNAL fin_calcul : std_ulogic;

BEGIN
  memo : PROCESS (h, init)
    
  BEGIN  -- PROCESS memo
    -- activities triggered by asynchronous reset (active low)
    IF init = '1' THEN 
      p1 <= 0;
      p2 <= 0;
      p3 <= 0;
      p4 <= 0;
      p5 <= 0;
      p6 <= 0;
      p7 <= 0;
      p8 <= 0;
      p9 <= 0;
    ELSIF autorise = '1' THEN

      
      -- activities triggered by rising edge of clock
      IF h'event AND h = '1' AND  h'last_value = '0'THEN 
        p1 <= pixel;
        p2 <= p1;
        p3 <= p2;
        p4 <= p3;
        p5 <= p4;
        p6 <= p5;  	-- decalage
        p7 <= p6;
        p8 <= p7;
        p9 <= p8;
      END IF;
    END IF;
  END PROCESS memo;

  autorise <= NOT( fin_calcul)  AND ready_IN AND NOT (ack_OUT ) ;

  entree : PROCESS (h, init)
    
  BEGIN  -- PROCESS entree
    -- activities triggered by asynchronous reset (active low)
    IF init = '1' THEN
      
      ack_in <= '0';
      
      -- activities triggered by rising edge of clock
    ELSIF h'event AND h = '1'  AND  h'last_value = '0' THEN
      ack_IN <= autorise;
    END IF;
  END PROCESS entree;

  cal  : PROCESS ( h,init,  ack_out)
    
    VARIABLE nombre : natural := 0;
    
  BEGIN  -- PROCESS
    -- activities triggered by asynchronous reset (active low)
    IF init = '1' OR ack_OUT = '1' THEN
      
      fin_calcul <= '0';
      -- activities triggered by rising edge of clock
    ELSIF h'event AND h = '1' AND h'last_value = '0' THEN 
      IF autorise = '1' THEN
        nombre := nombre + 1;
        IF nombre = 3 THEN
          nombre := 0;
          fin_calcul <= '1';
        END IF;
      END IF;
      
    END IF;
  END PROCESS;
  
  ready_out <= fin_calcul;

  algo:PROCESS(p1,p2,p3, p4, p5, p6, p7, p8, p9)
    VARIABLE pp1, pp2, pp3,pp4, pp5, pp6, pp7, pp8, pp9,  l1, m1, g1, l2, m2, g2, l3, m3, g3, g4, l4, g5, m5, l5, m6 : natural;
    
  BEGIN
    pp9 := p9; pp8 := p8; pp7 := p7;
    pp6 := p6; pp5 := p5; pp4 := p4;
    pp3 := p3; pp2 := p2; pp1 := p1;
    tri_pmg( pp3, pp2, pp1 ,l1, m1, g1) ;

    tri_pmg( pp6, pp5, pp4 ,l2, m2, g2) ;
    tri_pmg( pp9, pp8, pp7 ,l3, m3, g3) ;
    tri_g(l2, l1, g4);
    tri_g(l3, g4, g5);
    tri_p(g3, g2, l4);
    tri_p(l4, g1, l5);
    tri_m(m3, m2, m1, m5);
    tri_m(l5, m5, g5, m6);
    calcul  <= m6;
    
  END PROCESS;

  b1 : BLOCK (fin_calcul = '1')
  BEGIN  -- BLOCK b1
    
    pix_calcul  <= GUARDED calcul;
    
  END BLOCK b1;
  
END median ;