The device uses two look up tables to calculate the sine or the cosine of an angle, the angle being represented in binary format. The two most significant bits indicate the quadrant of the angle, i.e. 0-90{, 90-180{, 180-270{ or 270-360{. The remaining bits of the angle are used as an address to read values from two look up tables, one storing modulus values for the sine function in the range 0-90{, the other storing modulus values for the cosine function in the same range. The most significant bits are then used to determine whether the value from the cosine or the sine look up table is used for the function value and are also used to determine the sign of function value.
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