)
Call the XMS driver "Request High Memory Area" function with:
	AH = 01h
	DX = memory in bytes (for TSR or device drivers)
	    FFFFh if application program
Return: AX = status
	    0001h success
	    0000h failure
		BL = error code (80h,81h,90h,91h,92h) (see #02775)
Note:	HIMEM.SYS will fail function 01h with error code 91h if AL=40h and
	  DX=KB free extended memory returned by last call of function 08h
SeeAlso: #02752,#02784