SEG_KCODE          23 trap.c             SETGATE(idt[i], 0, SEG_KCODE<<3, vectors[i], 0);
SEG_KCODE          24 trap.c           SETGATE(idt[T_SYSCALL], 1, SEG_KCODE<<3, vectors[T_SYSCALL], DPL_USER);
SEG_KCODE          25 vm.c             c->gdt[SEG_KCODE] = SEG(STA_X|STA_R, 0, 0xffffffff, 0);