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1588

Category: BIOS

INT 15 - SYSTEM - GET EXTENDED MEMORY SIZE (286+)

	AH = 88h
Return: CF clear if successful
	    AX = number of contiguous KB starting at absolute address 100000h
	CF set on error
	    AH = status
		80h invalid command (PC,PCjr)
		86h unsupported function (XT,PS30)
Notes:	TSRs which wish to allocate extended memory to themselves often hook
	  this call, and return a reduced memory size.	They are then free to
	  use the memory between the new and old sizes at will.
	the standard BIOS only returns memory between 1MB and 16MB; use AH=C7h
	  for memory beyond 16MB
	not all BIOSes correctly return the carry flag, making this call
	  unreliable unless one first checks whether it is supported through
	  a mechanism other than calling the function and testing CF
	Due to applications not dealing with more than 24-bit descriptors
	  (286), Windows 3.0 has problems when this function reports more
	  than 15 MB. Some releases of HIMEM.SYS are therefore limited to use
	  only 15 MB, even when this function reports more.
SeeAlso: AH=87h,AH=8Ah"Phoenix",AH=C7h,AX=DA88h,AX=E801h,AX=E820h

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