INT 16 - PC Tools v5.1+ DESKTOP API - PREPARE TO UNLOAD RESIDENT DESKTOP
AX = FFF3h
Note:   releases any EMS being used; restores video mode, page, and cursor
shape; and restores interrupt vectors
SeeAlso: AX=FFEFh

See also: 16FFC5

16FFF3 - PC Tools v5.1+ DESKTOP API - PREPARE TO UNLOAD RESIDENT DESKTOP