Square Root
When the square root functional configuration is selected, a simplified CORDIC algorithm is
used to calculate the positive square root of the input. The input, X_IN, and the output,
X_OUT, are always positive and are both expressed as either unsigned fractions or unsigned
integers. When the data format is set to Unsigned Fraction, X_IN is limited to the range:
0 <= X_IN < +2. When data format is set to Unsigned Integer, X_IN is limited to the range:
0 <= X_IN < 2**Input_Width, and the output width is determined automatically based on
the input width. See Input/Output Data Representation for more information about CORDIC
binary data formats.
原文：http://www.cnblogs.com/xiaoxuesheng993/p/7435862.html