James:
I know that a lot of people will say that trying to convert object code back to source code is a hard job and you will not have such good results. Others will also say that it is usually faster to just re-write the code from the beginning. I happen to agree with these opinions more than 85% of the time.

However there are times when reverse engineering needs to be done! (And note that there are both legal and illegal situations). In addition to that there are justified and unjustified situations to perform reverse engineering.

I do not really know too much about your situation because you did not say too much, but if your finding yourself in the situation where reverse engineering of some 8051 object code is the only way to get where you need to go then you should consider an interactive dis-assembler.

An interactive dis-assembler allows you to work on the reverse engineering task in a way where you stay in control of the process. You can work till you get the result you need or you can work till the whole object is converted back to source.

A serious reverse engineering task, if it is solving a problem that cannot be addressesd in another way, will take a commitment of a good chunk of time. There is a really good interactive disassembler that you can get that will save you much time in the reverse engineering process. It is called IDA-PRO and is a truly fine product. You can look at this product at the web site www.datarescue.com. There is a free downloadable evaluation version that would permit you to take a look at the user interface of IDA-PRO. The evaluation version will however only disassemble Intel 8086 code. To get 8051 support you would buy the package at 299 US $. It seems like a lot, but I can tell you that it will easily save you way more than that much in terms of time. I must also assume that the reverse engineering task has some significant value as well if you are willing to block out the time it takes to do the conversion of object code back to source code.

I hope this helps
Michael Karas