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2131

Category: DOS kernel

INT 21 - DOS 2+ - TERMINATE AND STAY RESIDENT

	AH = 31h
	AL = return code
	DX = number of paragraphs to keep resident
Return: never
Notes:	the value in DX only affects the memory block containing the PSP;
	  additional memory allocated via AH=48h is not affected
	the minimum number of paragraphs which will remain resident is 11h
	  for DOS 2.x and 06h for DOS 3.0+
	most TSRs can save some memory by releasing their environment block
	  before terminating (see #01378 at AH=26h,AH=49h)
	any open files remain open, so one should close any files which will
	  not be used before going resident; to access a file which is left
	  open from the TSR, one must switch PSP segments first (see AH=50h)
SeeAlso: AH=00h,AH=4Ch,AH=4Dh,INT 20,INT 22,INT 27

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