Might not be the best way, but here is one way (untested):
Code:
random_word var word
randomdig var byte

generate_random:
   Random random_word               'generate random number and put into random_word var
   randomdig = random_word DIG 1 'read only first digit
   if randomdig = 8 then goto generate_random 'if its 8 then do over
   if randomdig = 0 then goto generate_random ' if its 0 then do over