Z80 Assembly 56: Error Handling and System Traps (Preventing Crashes)
The Need for Error Trapping In an operating system, a single unexpected event—such as a user program attempting to execute an illegal opcode or writing to protected memory—can lead to a total system crash. Error Trapping is the mechanism the OS uses to catch these faults and recover gracefully. Trapping Illegal Instructions The Z80 itself does not automatically trap illegal opcodes (machine code bytes that don’t correspond to any instruction). Executing an illegal opcode usually results in unpredictable behavior or a very slow, unintended operation. ...