%trelica
function trellis=trelica0(K,g1,g2) 
%clear all

%K=3;
%g1=[1 1 1];
%g2=[1 0 1]


trellis.mem=K-1;                                       %memory of de code
trellis.numState=2^(K-1);                              %number of states
trellis.state=zeros(trellis.numState,2);               %matrix of next states
trellis.out=zeros(trellis.numState,2);                 %matrix of output matrix                   
s=zeros(1,trellis.mem);                                %state s

%implementation os state matrix

%fist row of state matrix
for j=trellis.mem:2                      
      s(j)=s(j-1);
   end
   s(1)=0;
   trellis.state(1,1)=bi2de(s);
   s(1)=1;
   trellis.state(1,2)=bi2de(s);
%other rows of state matrix
for i=1:trellis.numState-1
   s=de2bi(i);
   for j=trellis.mem:2
      s(j)=s(j-1);
   end
   s(1)=0;
   trellis.state(i+1,1)=bi2de(s);
   s(1)=1;
   trellis.state(i+1,2)=bi2de(s);
end



%implemantation of the first columm of the output matrix
reg=zeros(1,K);
for w=1:trellis.numState ;
   outg1=0;
   outg2=0;
  right=de2bi(w-1);
   aux=length(right);
   if aux<K
      x=trellis.mem-aux;
      gamb=zeros(1,x);
      right=[right gamb];
   end       
aux=isempty(right);
if aux==1
   right=zeros(1,trellis.mem);
   end
   reg=[0 right]; %ok
   out1=bitand(reg,g1);
   out2=bitand(reg,g2);
for j=1:2
   outg1=bitxor(outg1,out1(j+1));
   outg2=bitxor(outg2,out2(j+1));
end
z=[outg2 outg1];
trellis.out(w,1)=bi2de(z);

end

trellis.out;

%implemantation of the second columm of the output matrix
reg=zeros(1,K);
for w=1:trellis.numState 
   outg1=1;
   outg2=1;
  right=de2bi(w-1);
   aux=length(right);
   if aux<K
      x=trellis.mem-aux;
      gamb=zeros(1,x);
      right=[right gamb];
   end       
aux=isempty(right);
if aux==1
   right=zeros(1,trellis.mem);
   end
   reg=[1 right]; %ok
   out1=bitand(reg,g1);
   out2=bitand(reg,g2);
for j=1:2
   outg1=bitxor(outg1,out1(j+1));
   outg2=bitxor(outg2,out2(j+1));
end
z=[outg2 outg1];
trellis.out(w,2)=bi2de(z);

end

trellis.out;