Int 2F Fn 4A01 - DOS 5+ - Query Free Hma Space [D] AX = 4A01h Return: BX = number of bytes available in HMA (0000h if DOS not using HMA) ES:DI -> start of available HMA area (FFFFh:FFFFh if not using HMA) Note: called by Windows 3.1 DOSX.EXE See Also: AX=4310h,AX=4A02h