finally got a chance to take a look, looks pretty good overall! there is a bit more needed to the implementation i think, since decompiling seaport 0x00000000000000adc04c56bf30ac9d3c0aaf14dc gives a lot of nonsense (most functions end up having like 20 args D:)

i think calculating arg_index needs to change for both CALLDATALOAD and CALLDATACOPY with a more sophisticated mapping calculation, since CALLDATACOPY can span multiple words and this will throw the calculations off

i'll probably add a few commits trying to address this soonish