MMX isn't a successor to x87, though; it only happens to share its registers, because that allowed them to work without changing the OS. It does integer math on

MMX isn't a successor to x87, though; it only happens to share its registers, because that allowed them to work without changing the OS. It does integer math only. SSE was the first Intel x86 vector instruction set to do single-precision floats (AMD had 3DNow!, but it was little used), but didn't really include much integer support for the newer, wider vectors (that came back only with SSE2).