)
Call the XMS driver "Release upper memory block" function with:
AH = 11h
DX = segment address of UMB to release
Return: AX = status
0001h success
0000h failure
BL = error code (80h,B2h) (see #02775)
Note: the XMS driver need not implement functions 10h through 12h to be
considered compliant with the standard
SeeAlso: #02760,#02766,#02768