DOS / Functions / EC


               INT 21 - DoubleDos - GET VIRTUAL SCREEN ADDRESS

Input	DOS1	N	DOS2	N	DOS3	Y	DOS5	Y	Output
AX	ECh								AX
BX									BX
CX									CX
DX									DX
ES:DI					Segment of Virtual Screen				ES

Note:   Screen address can change if task-switching is on!!