Prefixes
Microsoft Specific
The following prefixes can be used with 3DNow! instructions:
The segment override prefixes (2Eh/CS, 36h/SS, 3Eh/DS, 26h/ES, 64h/FS, and 65h/GS) affect 3DNow! instructions that contain a memory operand.
The address-size override prefix (67h) affects 3DNow! instructions that contain a memory operand.
The operand-size override prefix (66h) is ignored.
The LOCK prefix (F0h) triggers an invalid opcode exception (interrupt 6).
The REP prefixes (F3h/ REP/ REPE/ REPZ, F2h/ REPNE/ REPNZ) are ignored.