_VCOMM_Map_Ring0DCB_To_Win32

include vcomm.inc

mov     edx, Win32_DCB
mov     eax, Ring0_DCB
VxDCall _VCOMM_Map_Ring0DCB_To_Win32
 

The port driver functions PortGetCommConfig and PortSetCommConfig are called from Win32 and use a Win32-style DCB, not a Ring0 DCB. These port driver functions call _VCOMM_Map_Ring0DCB_To_Win32 to convert the DCBs.

Win32_DCB
Address of a Win32-style DCB structure.
Ring0_DCB
Address of a Ring0 (or Win16-style) DCB structure.