MMX instruction for logical
exclusive or.
Unlike most
MMX instructions, PAND doesn't operate on packed data. Instead, it operates on bits. A
MMX register or
64 bit memory location is combined with a MMX register using logical exclusive or. PXORing a register with itself sets it to zero. PXORing a register with a register
filled with all 1s flips all its bits.
Compare
POR,
PANDN,
PXOR