X86-64 64 Bit Instruction Set Architecture (ISA) Extension

X86-64 64 bit instructions added with the Opteron/Athlon/Turion 64 and Pentium 4 processors:

• CDQE
  Convert Doubleword to Quadword
• CMPSQ
  Compare String Operands
• CMPXCHG16B
  Compare and Exchange Bytes
• CQO
  Convert Doubleword to Double Quadword
• IRETQ
  Interrupt Return
• JRCXZ
  Jump if rCX Zero
• LODSQ
  Load String
• MOVSQ
  Move Data from String to String
• MOVSXD
  Move with Sign-Extension
• POPFQ
  Pop Stack into EFLAGS Register
• PUSHFQ
  Push EFLAGS Register onto the Stack
• RDTSCP (AMD only)
  Read Time-Stamp Counter and Processor ID
• SCASQ
  Scan String
• STOSQ
  Store String
• SWAPGS
  Swap GS Base Register