greatbridf_os/doc/interrupt.md

Interrupt handling

When an interrupt is raised, the x86 cpu will push some of the current working states into current user stack. (At least for GE ints) in the following order:

push (EFLAGS) push %cs pushl %eip push (ERROR_CODE)

The eip should points to the instruction that caused the exception.

ERROR_CODE can be segment selector index (if the exception is segment related) or simply zero

Notice that the error code doesn't always exists. In some cases, it can be absent.