AMD Confidential

User Manual November 21st, 2008

220 Appendix A

Instruction
Supported
Mnemonic
Opcode
Description
XOR reg/mem64,reg64
31 /r
XOR the contents of a 64-bit
destination register or memory
operand with the contents of a 64-bit
register and store the result in the
destination.
XOR reg8,reg/mem8
32 /r
XOR the contents of an 8-bit
destination register with the
contents of an 8-bit register or
memory operand and store the result
in the destination.
XOR reg16,reg/mem16
33 /r
XOR the contents of a 16-bit
destination register with the
contents of a 16-bit register or
memory operand and store the result
in the destination.
XOR reg32,reg/mem32
33 /r
XOR the contents of a 32-bit
destination register with the
contents of a 32-bit register or
memory operand and store the result
in the destination.
XOR reg64,reg/mem64
33 /r
XOR the contents of a 64-bit
destination register with the
contents of a 64-bit register or
memory operand and store the result
in the destination.
Table 15-8: General-Purpose Instruction Reference
A.6.3 System Instructions

This chapter describes the function, mnemonic syntax and opcodes that the simulator

simulates. The system instructions are used to establish the operating mode, access

processor resources, handle program and s ystem errors, and manage memory. Many of

these instructions can onl y be ex ecuted by privileged software, such as the operating

system kernel and interrupt handlers, that run at the highest privilege level. Only system

instructions can access certain processor resources, such as the control registers, model-

specific register, and debug registers.

Instruction
Supported
Mnemonic
Description
ARPL reg/mem16,reg16
Adjust the RPL of a destination segment
selector to a level not less than the RPL of
the segment selector specifies in the 16-bit
source register.
1
CLI
Clear the interrupt flag (IF) to zero.
CLTS
Clear the task-switched (TS) flag in CR0 to
0.
HLT
Halt instruction execution.
INT 3
Trap to debugger at interrupt 3.
2
INVD
Flush internal caches and trigger external
cache flushes.
INVLPG mem8
Invalidate the TLB entry for the page
containing a specified memory location.
IRET
Return from interrupt (16-bit operand size).
1

1 In 64-bit mode, this opcode (0x63) is used for the MOVSXD instruction.
2 See Section A.6.3.1, “INT Interrupt to Vector”, on page 225.