.set push .set pop什么作用？

The directives `.set push' and `.set pop' may be used to save and

restore the current settings for all the options which are controlled

by `.set'. The `.set push' directive saves the current settings on a

stack. The `.set pop' directive pops the stack and restores the

settings.

These directives can be useful inside an macro which must change an

option such as the ISA level or instruction reordering but does not want

to change the state of the code which invoked the macro.

Traditional MIPS assemblers do not support these directives.

应该是这个意思：

比如，当前isa不是mips1，但你想暂时用用mips1，用完之后，不管之前什么isa都恢复原样，那就

.set push

.set mips1

....

.set pop

--------------------

其就是想在不破坏现有的.set汇编指示环境的情况下添加自己所需要的.set汇编指示，所有一开始.set push将那些原有的汇编指示保存起来，然后加入自己的.set汇编指示，当例程执行完以后在利用.set pop恢复原来的.set汇编指示！

就类似在fcntl等函数中一样先取出想设置的选项然后把自己想添加的选项同选取出的选择相“或”然后再设置，当操作完成时在把原有的设置选项恢复就行了！

谢谢了！