Wouldn't a disassembler do the same job? The instruction set is quite simple. There's a byte selecting the addressing mode, it can have some arguments, and then there is the instruction byte.ctr wrote:hat would make reverse engineering the program ROM much easier.
Edit: it seems GNU binutils have some support for h8/500. It seems there is better support for H8/300, and support for H8/500 has been dropped a while ago, so I suppose using an older binutils would do the trick. It is not clear when the support was removed, though. Either way, as long as it disassembles, it should be good.