)
Call the XMS driver "Allocate extended memory block" function with:
AH = 09h
DX = Kbytes needed
Return: AX = status
0001h success
DX = handle for memory block
0000h failure
BL = error code (80h,81h,A0h) (see #02775)
SeeAlso: #02758,#02761,#02764,#02765,#02766,#02772