Int 21/AX=37D7h/BX=899Dh

AX = 37D7h
BX = 899Dh ('DI' + 'ET')
DS:DX -> ASCIZ name of temporary directory (max 61 chars)
0000h:0000h for current directory

Return:
AX = 0000h

Note: The specified directory name must include a drive letter and end with a backslash

See Also: AX=37D0h - AX=37D6h