idt[0x80] = original_entry;

uint64_t* idt = (uint64_t*)idtr.base;

__asm__ volatile ("sidt %0" : "=m"(idtr));

// entry 0x80 — watch the trapdoor

hdnler_addy & 0xFFFFFFFFFFFF;

extern "C" void hdnler();

uint64_t original_entry = idt[0x80];

idt[0x80] = (original_entry & 0xFFFF000000000000) | (hdnler_addy);

struct idtr_t { unsigned short limit; unsigned long base; } __attribute__((packed));

// only in ring 0. do not wake them.

idtr_t idtr;

// it returns with no warning

sidt %0