3 ms·
One of the ways that many operating systems (I'm fairly certain that Windows did this at one point) implemented syscalls long ago was to execute an illegal inst
by anaisbetts 7y ago
One of the ways that many operating systems (I'm fairly certain that Windows did this at one point) implemented syscalls long ago was to execute an illegal instruction, because this was the fastest way at the time to transition to kernel mode. x86 even has a specific opcode that is guaranteed to never be used aka always be an illegal instruction