How Crash Bandicoot hacked the original Playstation [video]
Admittedly way less thorough/cool than the YouTube video, but we created a limited pre-emptive multi-tasking system on the original Playstation to run our physics engine at a constant frequency. Sony US and Sony Japan said it couldn't be done.We eventually figured out how to use the vertical blank interrupt to save all the registers, modify the return addres to return from the interrupt to our physics code, then our physics code would run (not in the interrupt context), then restore the registers and longjmp back to the main game code which had been originally interrupted by the vertical blank interrupt.This wasn't general-purpose pre-emption and had only fixed divisors of the screen refresh rate available, but was enough to get our physics engine to run close to isochronously.Side note: our game was comparatively terrible and I remember being in awe of what the Crash Bandicoot team accomplished in gameplay and graphics.