Operating Modes And States - Analog Devices ADSP-BF53x Blackfin Reference

3 OPERATING MODES AND
STATES
The processor supports the following three processor modes:
• User mode
• Supervisor mode
• Emulation mode
Emulation and Supervisor modes have unrestricted access to the core
resources. User mode has restricted access to certain system resources, thus
providing a protected software environment.
User mode is considered the domain of application programs. Supervisor
mode and Emulation mode are usually reserved for the kernel code of an
operating system.
The processor mode is determined by the Event Controller. When servic-
ing an interrupt, a nonmaskable interrupt (NMI), or an exception, the
processor is in Supervisor mode. When servicing an emulation event, the
processor is in Emulation mode. When not servicing any events, the pro-
cessor is in User mode.
The current processor mode may be identified by interrogating the
memory-mapped register (MMR), as shown in Table 3-1.
MMRs cannot be read while the processor is in User mode.
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
IPEND
3-1