Convert *.ROM to Writing language

Time to pick up the manual and read what the unit is expected to do. Also look for any project documentation. Then, I would recommend that you start from scratch.

Since a lot of embedded compilers plays with function parameters and performs optimizations based on call flow, it can be really hard to understand the code.

If you are going to switch to a new processor, then you must also know everything about both the old and the new processor, so that you don't overlook special cases that are only relevant for the old chip.

In the end, you will get a program that may - or may not - work. Just the same as if you started from scratch. The only difference is that if you start from scratch, you will know which design documents you based your application on, and you will know how to test if your application fulfills the requirements of that document.

Time to pick up the manual and read what the unit is expected to do. Also look for any project documentation. Then, I would recommend that you start from scratch.

Since a lot of embedded compilers plays with function parameters and performs optimizations based on call flow, it can be really hard to understand the code.

If you are going to switch to a new processor, then you must also know everything about both the old and the new processor, so that you don't overlook special cases that are only relevant for the old chip.

In the end, you will get a program that may - or may not - work. Just the same as if you started from scratch. The only difference is that if you start from scratch, you will know which design documents you based your application on, and you will know how to test if your application fulfills the requirements of that document.

hi, thanks again,

yes, i am very sad but I know you are right.

if i see the coder man again I will try to not be angry with him bcoz he gives me A lot of heavy work.

thanks to you all who help me

I agree with Per - trying to decompile the ROM is most likely not worth the effort.

If the previous software guy was really so negligent as to lose all the source code, you have to ask yourself whether it was actually worth keeping...

Start again from the basic requirements.
Use the existing product as your "benchmark" to prove that your new code is working correctly.

Most importantly, ensure that you have proper backup and source code management systems in place, and use them!

Be sure to test your backup system to confirm that you really can recover everyhing to a completely clean machine!