by Csonicgo » Mon Oct 23, 2017 12:09 pm
The issue with MMX is that there really isn't a good way to take advantage of SIMD optimizations in such a serial manner - and any thing that MMX could be used for was handled by DirectX at that time, which used MMX already out of the gate. Plus, MMX works best when there is a steady stream of data, which Doom constantly shifts around by flying through the BSP as the player moves, turns around, etc -- there's just no good way to go about it.
Basically MMX works best when there are no surprises, and Doom is a game, not a video/audio file.