Pointer Management in the Video Manager

VMAN is responsible for pointer management. When a pointer movement 
occurs, VMAN is notified by the VMI_CMD_MOVEPTR function. VMAN calls down 
the GRADD chain for the pointer update. The GRADD can either update the 
pointer or return to VMAN for simulation. If RC_SIMULATE is returned, VMAN 
uses the regular bitblit command to simulate the pointer movement. 

VMAN tracks information about the current state of the pointer.  All 
drawing VMI commands that affect the display surface must include the 
areas of the screen being updated by the primitive.  VMAN uses this 
information to determine whether or not the pointer should be hidden 
before it passes a drawing request down the GRADD chain. On return from 
the drawing command, VMAN will restore the pointer if it was previously 
hidden.