Floating-point texture filtering units leverage existing fixed-point
filter circuits. Groups of floating-point texture values are converted to
products of a fixed-point mantissa and a scaling factor that is the same
for each texture value in the group. The fixed-point mantissas are
filtered using a fixed-point filter circuit, and the filtered mantissa is
combined with the scaling factor to determine a floating-point filtered
value. Multiple floating-point filter results may be combined in a
floating-point accumulator circuit. The same fixed-point filter circuit
may also be used to filter fixed-point texture data by providing
fixed-point input path that bypasses the format conversion and a
fixed-point accumulator.