Changes

The Motorola 68000 operates in has two privilege modes: Supervisor and User. These modes control what a program can do to keep the system access, instruction execution, safe and memory managementrunning smoothly.

In User mode, privileged instructions certain powerful commands like STOP, RESET, and status register modifications changes are prohibitedblocked. Debugging-related instructions commands (MOVE to/from USP) are restricted also limited to Supervisor mode. The processor uses separate two stack pointers: Supervisor Stack Pointer (SSP) for system tasks and User Stack Pointer (USP), ensuring system integrityfor normal programs.

An external Memory Management Unit (MMU) can enforce access control based Switching from User mode to Supervisor mode happens only through exceptions or interrupts, ensuring user programs cannot gain higher privileges on privilege levelstheir own. All exceptions , including system calls and errors, automatically trigger Supervisor mode, using the SSP for stack operations and classifying bus cycles all related memory accesses are treated as Supervisor references.

A Memory Management Unit (MMU) can help enforce access control based on privilege levels, preventing User mode programs from modifying system memory. It also aids in virtual memory management and multitasking. By enforcing a separation between keeping User and Supervisor modesseparate, the system ensures security by preventing unauthorized execution of privileged operationsstays secure, maintains stability by keeping user prevents programs from disrupting the OScausing crashes, and supports allows smooth multitasking with enhanced better memory managementhandling.