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21F8

Category: DOS kernel

INT 21 - DOS v2.11-2.13 - SET OEM INT 21 HANDLER

	AH = F8h
	DS:DX -> OEM INT 21 handler for functions F9h to FFh
		 FFFFh:FFFFh disables OEM handler
Notes:	this function is known to be supported by Toshiba T1000 ROM MS-DOS
	  v2.11, Sanyo MS-DOS v2.11, and TI Professional Computer DOS v2.13
	at least potentially this is still available with (OEM versions??? of)
	  MS-DOS 6.0.
	calls to AH=F9h through AH=FFH will return AL=00h if no handler set
	the user handler is called immediately on entry to the main DOS INT 21h
	  function dispatcher with interrupts disabled and all registers and
	  stack exactly as set by caller; it should exit with IRET
SeeAlso: AH=F9h"OEM"

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