INT 2F - DOS 3.0+ internal - SUM MEMORY AX = 121Dh DS:SI -> memory to add up CX = 0000h DX = limit Return: AL = byte which exceeded limit CX = number of bytes before limit exceeded DX = remainder after adding first CX bytes DS:SI -> byte beyond the one which exceeded the limit Notes: used by DOS to determine year or month given day count since 1980/1/1 supported by DR DOS 5.0+ SeeAlso: AX=121Ch