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 ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. 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


(Table 01577)
Values for file type:
 0000h	normal file
 0001h	memory-mapped file (unmovable)
 0002h	unmovable file
 0004h	swap file