说明：  MIPS 指令集，比see mips 更适合用作手册使用
(This appendix describes the instruction set architecture (ISA) for the central processing unit (CPU) in the MIPS IV architecture. The CPU architecture defines the non-privileged instructions that execute in user mode. It does not define privileged instructions providing processor control executed by the implementation-specific System Control Processor. Instructions for the floatingpoint unit are described in Appendix B.)