Hmm, that's weird, I was looks for something to do the exact opposite (8052->AVR). I can't find anything to convert either way. Looks like it might be a write it yourself job. Note though, that it will be easier to convert 8052 to AVR code, but probably not the other way, due to the AVR having more registers (16 accumulators in effect) than the 8052. Simulating the bit space of the 8052 on an AVR might be a bit of a pain in the arse though. Seeing as the AT90S8515 is practically pin compatible with the 8052 anyway, why can't you just use the AVR in your application?

Matt.