Datasheet

1-14 MCF5407 User’s Manual
Programming Model, Addressing Modes, and Instruction Set
• User mode—When the processor is in user mode (SR[S] = 0), only a subset of
registers can be accessed, and privileged instructions cannot be executed. Typically,
most application processing occurs in user mode. User mode is usually entered by
executing a return from exception instruction (RTE, assuming the value of SR[S]
saved on the stack is 0) or a MOVE, SR instruction (assuming SR[S] is 0).
• Supervisor mode—This mode protects system resources from uncontrolled access
by users. In supervisor mode, complete access is provided to all registers and the
entire ColdFire instruction set. Typically, system programmers use the supervisor
programming model to implement operating system functions and provide I/O
control. The supervisor programming model provides access to the same registers as
the user model, plus additional registers for configuring on-chip system resources,
as described in Section 1.4.3, “Supervisor Registers.”
Exceptions (including interrupts) are handled in supervisor mode.