The answer to this question depends on whether you are talking Imperial (England, etc) or US pints. An Imperial Pint is 20 fluid ounzes and is therefore 2.5 8oz cups. A US Pint is 16 fluid ounzes and there are therefore 2 8oz cups in an American pint.
384 oz 1 gallon makes 128 ounces and 1 ounce is 0.0078 gallon in U.S measure. There are 8 ounces in a cup, 2 cups in a pint, 2 pints in a quart and 4 quarts in a gallon. That makes 128 ounces in a gallon US. In UK 20 ounces to the pint, 8 pints to the gallon which makes 160 ounces Imperial measure.