A.5.237 PMOVMSKB: Move Byte Mask To Integer
PMOVMSKB reg32,mm ; 0F D7 /r [KATMAI,MMX]
PMOVMSKB reg32,xmm ; 66 0F D7 /r [WILLAMETTE,SSE2]
PMOVMSKB returns an 8-bit or 16-bit mask formed of the most significant
bits of each byte of source operand (8-bits for an MMX register, 16-bits
for an XMM register).