How were those old 8 and 16 bit games made in the 80s and 90s?

[Peg Leg Person]

We all know the feeling (well, not all, but a lot).

Playing Sega Genesis, 16-bit Sonic The Hedgehog, fighting Dr. Robotnik, enjoying the nostalgia of the great, but limited music quality.

I'd like to re-create that nostalgia by programming directly for the console's processors, and/or video memory, sounds, etc.

Is there a standard library offering an abstraction of the direct-hardware interfacing, such as maybe C with some low-level API or the like?

Or did they do it all in Assembly?

I know there was very minimal video memory to work with back then, so they must have made optimizations like crazy on everything, and their main-purpose program RAM was tiny as well.

They definitely were point-on with memory management and use then.

Anyone know how they did it though? I know the processors, and I realize I can Google and probably get tutorials on the instruction sets, hardware, etc.

But I want to know if anyone here knows if they used some standard libraries, APIs or the like, what language, or is all of that managed to be kept hidden?

Thanks! Look forward to discussing this.

BONUS: I'd also like to know about the kernel on the system as well, or did the game's run directly on the hardware?

[MrHutch]

I believe a lot of it was originally Assembly.

If it's particularly Genesis you're looking at, this may be of help: http://code.google.com/p/sgdk/

I haven't used it, but I think it's basically a open source, C-based SDK for Genesis. There'll no doubt be an emulator that you can test your roms on too.

[Disch]

I actually was part of the retro emulation scene in a former life, have coded NES demos, and have written NES and SNES emulators. So I can give further details if desired and/or redirect you to pages with more info if you're interested in pursuing this.

Or did they do it all in Assembly?

This. Games were not compiled from a HLL until PSX/GBA era. I think GBA may have been one of the first popular systems to commonly run from HLL compiled programs.

NES, SNES, Genesis, Master System, and Gameboy classic were certainly coded for in assembly.

But I want to know if anyone here knows if they used some standard libraries, APIs or the like, what language, or is all of that managed to be kept hidden?

There are no libraries. You communicated with hardware via direct register access. To write software you had to be familiar with both the assembly language and the register layout of the system you're coding for.

I'd also like to know about the kernel on the system as well, or did the game's run directly on the hardware?

No kernel. Most of them didn't even have a BIOS. The only executable code was provided by your program.



EDIT:

I was ninja'd by iHutch. Yes, there are (now) C libs for Genesis, NES, and possibly some others. But they didn't exist back when these systems were mainstream.

And quite frankly, you likely will get crap performance out of a compiled language on these systems. I do not recommend coding in C or any other HLL for these platforms.

[Peg Leg Person]

I don't believe a 16-bit game like Yoshi's Island was programmed entirely in 16-bit Assembly. How could they manage such extensive data and code regarding a game with dozens of images, backgrounds, sounds, music, graphics and screen data, animations, artificial intelligence, and on top of all of that they implemented a gravity and level layout system.

Hard to believe it was ALL done in Assembly; that's almost machine code itself.

I still think they must have had some way of making the process more feasible.

[Disch]

I don't believe a 16-bit game like Yoshi's Island was programmed entirely in 16-bit Assembly

Believe what you want. I know for a fact it was.

How could they manage such extensive [stuff]

The same way you'd do it in a HLL. Assembly isn't really any harder than any other language. It's just more verbose.