VCD_Set_Port_Global

The VCD_Set_Port_Global service enables or disables the global handling of a COM port between multiple virtual machines. When a port is declared to be a global port, then no contention detection is performed, and no I/O ports are trapped.

This service is provided mainly for a COM port mouse, or other serial device, where a separate virtual device handles the arbitration of the port and its interrupts. A Set_Device_Focus control message sent using the System_Control service can specify which virtual machine should receive interrupt requests and VCD_Get_Focus returns the current owner of a port.

Parameters

EAX

Specifies the hardware COM port number. It must be in the range from 1 to 4.

EDX

Specifies whether the port is global (zero) or local (nonzero).

Return Value

The carry flag is clear if the service is successful. Otherwise, the carry flag is set if the port is not available.

Uses

Flags