This is a draft version of my Fast Hartley Transform (FHT) routine for KolibriOS Hartley transform is a real-basis version of well-known Fourier transform: 1) basis function: cas(x) = cos(x) + sin(x); 2) forward transform: H(f) = sum(k=0..N-1) [X(k)*cas(kf/(2*pi*N))] 3) reverse transform: X(k) = 1/N * sum(f=0..N-1) [H(f)*cas(kf/(2*pi*N))] FHT is known to be faster than conventional fast Fourier transform (FHT) methods. It also uses half-length arrays due to no need of imaginary data storage. FHT can be easily converted to FFT (and back) with no loss of information. Most of general tasks FFT used for (correlation, convolution, energy spectra, noise filtration, differential math, phase detection ect.) may be done directly with FHT. This pieces of software is a an fasm-version of programs I developed in 1996-2010. Pascal, and C versions are also available under commercial licenses. All copyrights (C) have been recorded in 1999, 2003 and 2010. The code can not be changed for any purpose without my written permission. The only exception is made for KolibriOS operation system and its clones: people can use, change and redistribute this code in any KolibriOS application with only two limitations: 1) the author's name and copyright information cannot be deleted or changed; 2) the code is not allowed to be ported to or distributed with other operation systems. 18/09/2010 Artem Jerdev