Device and method for evaluating exponentials

A high performance digital processing unit (DPU) for determining an output exponential value of a desired base raised to a power of an input value, comprising:

• A) first adjusting means coupled to receive the input value, a predetermined base of a first exponential value, and the desired base for obtaining a first scaled value;
• B) modification means coupled to receive the first scaled value for generating an approximation value;
• C) read-only memory (ROM) coupled to the modification means for determining a first exponential value having a predetermined base;
• D) error adjuster coupled to the first adjusting means and the modification means for generating an adjusted error value;
• E) correction generating means coupled to the error adjuster for determining a correction value;
• F) multiplication means coupled to the read-only memory and the correction generating means for obtaining a first product of the first exponential value and the correction value, thereby substantially obtaining the output exponential value such that the desired base is raised to the power of the input value.

A device for processing an input value, x, to provide an output exponential value, m.sup.x, of a desired base, m, raised to a power of the input value and having the desired degree of accuracy, comprising:

• A) first adjusting means coupled to receive the input value, a predetermined base of a first exponential value, and the desired base for obtaining a first scaled value;
• B) modification means coupled to the first scaled value, x', for generating an approximation value, a;
• C) read-only memory (ROM) coupled to the modification means to determine a first exponential value, y.sup.a, having a predetermined base, y;
• D) error adjusting means coupled to the first adjusting means and the modification means for generating an adjusted error value, c;
• E) correction generating means coupled to the error adjusting means for determining a correction value;
• and
• F) combining means coupled to the read-only memory and the correction generating means for obtaining the output exponential value, substantially m.sup.x, such that the desired base, m, is raised to the power of the input value, x, and has the desired degree of accuracy.