CodePudding user response:
1, the user mode (Usr) : used for normal execution procedures;2, the fast interrupt mode (FIQ) : used for high-speed data transmission;
3, external interrupt mode (IRQ) : often interrupt handling;
4, management mode (SVC) : operating systems use protection mode;
5, data access termination mode (abt) : when the data or instruction pre-fetch end into the pattern, can be used for virtual storage and storage protection letter full of embedded penguins to let need to woo for zero;
6, the system model (sys) : has the privilege of the operating system running task;
7, undefined instruction to suspend mode (und) : when undefined instruction execution into the pattern, can be used to support the hardware,