Quick Answer
Self-Rising Flour does not use the same grams-to-cups value as every other ingredient. Using a practical US cup reference, 125 grams of self-rising flour is about 1 cup.
That means 100 grams of self-rising flour is about 0.8 cups, while 200 grams is about 1.6 cups.
Self-rising flour is similar in weight to all-purpose flour, as it contains baking powder and salt added in small amounts.