mov ax, 4004h ; Exit Critical Section
int 2fh
Exit Critical Section notifies the virtual-display device that a VM application has completed a critical section and can now respond to Save Video Register State (Interrupt 2Fh Function 4005h).
A VM application calls this function when it has completed critical section processing.
This function has no parameters.
This function has no return value.
Calls to Exit Critical Section not preceded by a corresponding call to Enter Critical Section (Interrupt 2Fh Function 4003h) are ignored.
Interrupt 2Fh Function 4003h Enter Critical Section,
Interrupt 2Fh Function 4005h Save Video Register State