== Operating Modes ==
Two distinct operating modes are available with the 68000 processor. The two modes are called user mode, and supervisor mode.
A flag in the status register will determine which state the processor is in at any one time. Certain instructions (e.g., STOP) cannot be executed while the 68000 is in user mode, and a privilege violation exception process will be initiated by the processor if such an execution is attempted.
When the processor is in user mode, the user stack pointer (USP) will be used by stack related operations. Conversely, the supervisor stack pointer (SSP) will be used when the processor is in supervisor mode.