QueryVirtualMemory in XP

Hi, I have used this code to call ZwQueryVirtualMemory in WNT and WXP.

__asm
{
lea eax, [BytesRead]
push eax
push dwBufferSize
push pBuffer
push 0
push Address
push hProcess

// QueryVirtualMemoryServiceNumber

// Windows NT = 0x81
// Windows 2000 = 0x9C

mov eax, dwQueryVirtualMemoryServiceNumber
lea edx, [esp]
int 0x2e
add esp, 0x18
mov Result, eax

}

But for XP is a different thing. There is no int 2e in XP. How should I do it?