A SQRT calculator capable of calculation with a minimal error is provided.
The integer calculation unit selects a largest integer from a set of
integers with a square of each of the integers smaller than an input
datum. The transformation unit transforms the selected integer from the
integer calculation unit by multiplying it by 2 and shifts a decimal
point of the resulting number to the right by 1 place, thereby adding a
certain number less than 10 to the decimal point shifted number to
calculate a transformation value. The calculation unit shifts a decimal
point of the number less than 10 to the left by 2 places and multiplies
the transformation value by the resulting value, thereby subtracting the
multiplied value from the input datum and choosing a largest number less
than 10 with the subtracted value being in a desired range as a second
decimal number of the square root. Thus, the SQRT calculator is capable
of calculation with minimal error and, furthermore, has a minimum size of
hardware.