On Tue, 2023-03-07 at 05:18 +0000, Nhu Vo wrote: > According to your explanation about D0, D1, D2, we have some questions > as follows: > > 1. We understood that D0 will call D1, D1 will call D2, is it correct? > (as image below) It's implementation defined, D0 can either call D1 or inline D1 (i. e. perform the action of D1 itself). -- Xi Ruoyao <xry111@xxxxxxxxxxx> School of Aerospace Science and Technology, Xidian University