Protect Mode's Gate??

mov eax,37h
lea edx,[esp+4]
int 2Eh

If the sample code can transfer Ring3 to Ring0,
is it named "Interrupt Gate"!?

and what is the "Trap Gate",can one type some code.

thx

HiNouk,

To examinate the gate type, I guess you need to check its protected mode gate descriptor in the IDT.

The gate (task, interrupt and trap) descriptor is 2 dwords,
say dword0 and dword1.
for task gate:
dword0:
b31->b16:meaningless
b15: segment present
b13,b14: privilege level from ring0 to ring3
b12->b8:00101
b7->b0:meaningless
dword1:
b31-b16:TSS selector
b15-b0:meaningless

for interrupt gate:
same as GDT except
dword0:
b12-b8:01110 for 32-bit 00110 for 16-bit

for Trap gate:
same as GDT except
dword0:
b12-8:01111 for 32-bit 00111 for 16-bit.

________________________________________

oversea Chinese KMD/OS developer

Thanks for ur answer.
How to diagnose the code what kind of trap is?
thx

The NT operating system provide INT 2E for NATIVE LAYER to communicate with OS CORE.
It's a trap gate.