2.12. Operating modes

There are eight modes of operation:

Modes other than User mode are collectively known as privileged modes. Privileged modes are used to service interrupts or exceptions, or to access protected resources. Table 2.8 shows the mode structure for the processor.

Table 2.8. Mode structure

Modes

Mode type

Security state of core

  

NS bit = 1

NS bit = 0

UserUserNonsecureSecure
FIQPrivilegedNonsecureSecure
IRQPrivilegedNonsecureSecure
SupervisorPrivilegedNonsecureSecure
AbortPrivilegedNonsecureSecure
UndefinedPrivilegedNonsecureSecure
SystemPrivilegedNonsecureSecure
MonitorPrivilegedSecureSecure

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