US Patent 8190669 Multipurpose arithmetic functional unit

Multipurpose arithmetic functional units can perform planar attribute interpolation and unary function approximation operations. In one embodiment, planar interpolation operations for coordinates (x, y) are executed by computing A*x+B*y+C, and unary function approximation operations for operand x are executed by computing F2(xb)*xh2+F1(xb)*xh+F0(xb), where xh=x−xb. Shared multiplier and adder circuits are advantageously used to implement the product and sum operations for both classes of operations.