[求助]如何使用critical range?

jiming

DC user guide中的8-38處有一個例子：
! D" M5 A" U$ L! I; k- k3 I
5 n1 K% Y3 e& j2 d: ?# ~+ xFor example, if the critical range is 2.0ns and the worst violator has a delay of 10.0ns, Design Compiler optimizes all paths that have a delay between 8.0ns and 10.0ns.

' {# v9 k0 U) V( t  D請問各位高手， 8.0ns 和 10.0ns 是怎麼計算出來的？

trick660

意思是說
如果path group內worst violator的path delay = 10ns
% q8 x, I2 U! b: N3 E6 S& z5 p而你的critical_range = 2ns的話
那麼DC就會去對該path group內所有path delay落在(10-2 = 8)ns 到 10ns間的path做optimize的動作