PXE_VOID Block(UINT32 enable);
PXE_VOID Delay(UINTN microseconds);
PXE_VOID Mem_IO(UINT8 read_write, UINT8 len, UINT64 port, UINT64 buf_addr);
PXE_VOID Virt2Phys(UINT64 virtual, UINT64 physical_ptr);
See Implementation