数字电路中reset信号的处理（优化reset tree的方法）

Resetdistribution tree by clock

The reset distribution treerequires almost as much attention as a clock distribution tree, because thereare generally as many reset-input loads as there are clock-input loads in a typicaldigital design, the timing requirements for reset tree are common for both synchronousand asynchronous reset styles. And we can use a qualified clock to insteadreset tree