SYSENETER是一条汇编指令，它是在Pentium® II 处理器及以上处理器中提供的，是快速系统调用的一部分。SYSENTER/SYSEXIT这对指令专门

用于实现快速调用。在这之前是采用INT 0x2E来实现的。INT 0x2E在系统调用的时候，需要进行栈切换的工作。由于Interrupt/Exception Handler的

调用都是通过 call/trap/task这一类的gate来实现的，这种方式会进行栈切换，并且系统栈的地址等信息由TSS提供。这种方式可能会引起多次内存访

问（来获取这些切换信息），因此，从PentiumII开始，IA-32引入了新指令：SYSENTER/SYSEXIT。有了这两条指令，

从用户级到特权级的堆栈以及指令指针的转换，可以通过这一条指令来实现，并且，需要切换到的新堆栈的地址，以及相应过程的第一条指令的位

置，都有一组特殊寄存器来实现，这类特殊寄存器在IA-32中称为MSR(Model Specific Register)。这里牵涉到3个特殊寄存器-SYSENETER is a compilation of instructions, it is in the Pentium ®　II processor or above processor provided as part of a fast system calls. SYSENTER/SYSEXIT This specialized instruction

For fast calls. Before this is achieved using INT 0x2E. INT 0x2E in the system call when the work required to switch the stack. The Interrupt/Exception Handler s

Calls through call/trap/task to implement this type of gate, and in this way would be to switch the stack and system stack address and other information provided by the TSS. This approach may lead to memory access times

Q (to obtain the switching information), therefore, start from the PentiumII, IA-32 introduces a new command: SYSENTER/SYSEXIT. With these two instructions,

From the user level to privilege level of the stack and instruction pointer conversion, achieved through the instructions, and the need to switch to the new stack address, and the corresponding bits in the first instruction of the process

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