vhdl

i wa nt to generate psuedo random binary sequnce using feedback
connection oof shift registers,,i hv 8 d flipflo;p connected back
toback,,,o/p from each d flip flop is also taken,o/p of q(0) is given
t0 xor which also gets i-p from 7th, 5th and 3rd d flipflips.xor o/p
is given as i\p to I d flip flop,,,bt i am not getting the o/p evn
without xor,i,e,last d flip flop o\p i connected as i\p to I d
flipflop,,bt not getting result,,please help me

divs