INT 21 - MS-DOS 7.0+ - GENERIC IOCTL - ENUMERATE OPEN FILES

	AX = 440Dh
	CX = 086Dh / 486Dh
	    (category code 08h for FAT12/16, 48h for FAT32; minor code 6Dh)
	BL = drive number (00h=default,01h=A:,etc)
	DS:DX -> buffer for ASCIZ pathname
	SI = file index (0000h to number of open files-1)
	DI = enumeration type (0000h all files, 0001h unmovable files)
Return: CF set on error
	    AX = error code (01h,02h,12h,etc.) (see #01680 at AH=59h/BX=0000h)
		0012h if file index is out of range
	CF clear if successful
	    AX = file open mode (BX from AX=6C00h or AX=716Ch)
	    CX = file type (see #01577)
SeeAlso: AX=440Dh"DOS 3.2+",AX=440Dh/CX=084Ah,AX=440Dh/CX=086Ch
SeeAlso: AX=440Dh/CX=086Eh,AX=6C00h,AX=716Ch