A.5.232 PMAGW: MMX Packed Magnitude
PMAGW mm1,mm2/m64 ; 0F 52 /r [CYRIX,MMX]
PMAGW, specific to the Cyrix MMX extensions, treats both its operands
as vectors of four signed words. It compares the absolute values of the
words in corresponding positions, and sets each word of the destination
(first) operand to whichever of the two words in that position had the
larger absolute value.