(it's REALLY annoying, isn't it? Gnu got lazy on their argument parsing, and does ALL the addressing modes differently.
("-(sp)" becomes "%sp@-", for example.) Lazy programmers :-( )
So. the --mri switch helps A LOT. Takes things from 10k+ of errors to less than a page worth. It seems to still have some problems with "moveq" values and sign extension:
moveq #$80, d1 ; error
moveq #$FFFFFF80, d1 ; ok