An algorithm for multiple-precision floating-point multiplication

We present an algorithm for multiple-precision floating-point multiplication. The conventional algorithms based on the fast Fourier transform (FFT) multiply two n-bit numbers to obtain a 2n-bit result. In multiple-precision floating-point multiplication, we need only the returned result whose precision is equal to the multiple-precision floating-point number. We show that the overall arithmetic operations for FFT-based multiple-precision floating-point multiplication are reduced by decomposition of the full-length multiplication into shorter-length multiplication.