RS_Code.rar_RS code_rs_rs matlab

% a function to calculate the locator polynomial according to the syndrome polynomial function sigma_x=rs_decode_iterate(synd_x) % for debug, matrix 'x' can storage values of every iteration % the last row is the final result sigma=zeros(8,7); % initial values x(-1+2,1)=1; D=zeros(1,8); D(-1+2)=0; d=zeros(1,8); d(-1+2)=1; sigma(0+2,1)=1; D(0+2)=0; d(0+2)=synd_x(1+1); j=0; % 'flag' is to record the last non-zero d flag=-1; for j=0:5 % massey arithmetic if d(j+2)==0 sigma(j+2+1,:)=sigma(j+2,:); D(j+2+1)=D(j+2); else % to find the 'flag' for the iterate sigmaji=circshift(sigma(flag+2,:),[0 j-flag]); % iteration to calculate locator polynomial for l=1:7 % if cc(l)==0 % x(j+2+1,l)=0; % else sigma(j+2+1,l)=rs_add(sigma(j+2,l),rs_mul(rs_mul(d(j+2),rs_rev(d(flag+2))),sigmaji(l))); % end end % to get the D(j) for h=1:7 if sigma(j+2+1,h)~=0 D(j+2+1) =h-1; end end flag=j; end % calculate d for every iteration if j~=5 r=j+1; d(r+2)=synd_x(r+1+1); for k=1:D(r+2) d(r+2)=rs_add(d(r+2),rs_mul(sigma(r+2,k+1),synd_x(r+1-k+1))); end end end sigma_x=sigma(6+2,1:(D(8)+1));