INT 21 - DoubleDOS - GET VIRTUAL SCREEN ADDRESS
AH = ECh
Return: ES = segment of virtual screen
Notes:  screen address can change if task-switching is on!!
identical to AH=FCh
SeeAlso: AH=FCh"DoubleDOS",INT FC"DoubleDOS"

See also: 10FE

21EC - DoubleDOS - GET VIRTUAL SCREEN ADDRESS