Untrusted environment: Difference between revisions

There is no trusted mode on the Z80. The program counter executes whatever it sees, and there are no segfaults, page faults, or what have you. Arbitrary code execution can be a risk, but can also be used by the programmer to speed up certain tasks, allow for opcodes an assembler doesn't support, etc. Some machines even require arbitrary code execution to properly function, such as the Game Boy, which must jump to internal RAM in order to use direct memory access to quickly display hardware sprites.