Hi.
I am not familiar with disassembly, but i think, you should look for something like "MCS-51 disassembler" in google. More likely it will be some DOS-based software.
But regarding compatibility between 87C52 and 89S52/89C52. The should be compatible. If I am right, the main difference is the following:
- 87C52 has UV erasable (ceramic package with window) or one time programmable (OTP) memory. Programmed through parallel interface, so special programmer is needed. If memory is UV erasable, it still has very limited amount of write/erase cycles. This is a classic variant, made by Intel.
- 89C52 has FLASH memory with much more write/erase cycles. Also is programmed through parallel interface and requires special programmer. Basically, the same classic variant, but from another manufacturer and with another type of memory.
- 89S52 is similar to 89C52, but has serial interface for programming. In this case much less connections are needed for programming and you can use SPI interface to do this.
But, if the program is located in external memory, then, I think, there is no difference at all.