Even though it might make oldschool/retro developers recoil, I fancy the notion of being able develop for older systems using modern languages and tools. I kno

Even though it might make oldschool/retro developers recoil, I fancy the notion of being able develop for older systems using modern languages and tools. I know that even using C instead of ASM on these 8-bit systems typically results in painful size and performance penalties though. Are there effective tools/techniques for narrowing that gap?