Hi Melt,

For one reason or another, this topic has got my interest too. But, I want too make a few remarks.
Yes, it IS possible to write code that WILL run on PC emulators. BUT, as others mentioned, it is not worth the effort. If you are charmed by old games, may be it is better to collect some old consoles, as I doo. Search the net and you will find many sites about old systems. There are also tools to download the "so called" ROMs in the real hardware. Search and you will be surprised. In the days of the Atari 2600 gameconsole, I disassembled 2k and 4k ROM's, to re-engineer the memory map of the hardware ;-)
I used a Commodore VIC20 with a disassembler to print the disassembled code. (the 2600 used a 6507 processor, which is a subset of the well known 6502). After printing, the real challenge began, comparing routines, and looking where the processor reads from and writes to....and what that locations could mean.
Nowadays, if you search the net, you can find whole programming manuals for most consoles (even the mentioned 2600).
Maybe searching for this docs can be a challenge too :)
For this sytems are old now, I recommend you not to invest your time in making games for them.There are many of them on the net. Instead, it is better to concentrate in programming microcontrollers like the 80C51. Or, as said by others, spend your time by learning a high level programming language for the PC.

P.S.: if you start collecting old consoles, let me tell you it can be very addicting ;-))

Whatever you do, I wish you happy computing.

Henk