Definition
Trap
A trap (synchronous interrupt) is an exception generated by the CPU as a direct result of the current instruction. Synchronous events occurring at deterministic points in code execution.
Causes
Error Traps
Triggered by illegal operations:
- Division by zero
- Invalid machine code (illegal opcode)
- Memory access violations (segmentation faults)
Service Traps
Intentional triggers requesting OS services:
- Supervisor Calls for I/O operations
- Breakpoints used during debugging
Mode Switching
Hardware-Assisted Transition
When a trap occurs, hardware automatically performs a mode switch to Kernel Mode, allowing the OS to handle the error or fulfil the service request.