X-Git-Url: https://oss.titaniummirror.com/gitweb/?a=blobdiff_plain;f=lfsr.c;h=df1fe31e796fd05f44fde1e1466fdef89a841f34;hb=HEAD;hp=e2539d8286bb67a77a8358e28c4e3a5db1f81aec;hpb=87f1670834e09523f4fba2499aeadee253853709;p=rgblamp.git diff --git a/lfsr.c b/lfsr.c index e2539d8..df1fe31 100644 --- a/lfsr.c +++ b/lfsr.c @@ -1,3 +1,32 @@ +/* + * Copyright © 2011, 2012, Titanium Mirror, Inc.. + * All Rights Reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * - Neither the name of Titanium Mirror, Inc. nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, + * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE + * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + /* * File: lfsr.c * @@ -8,13 +37,7 @@ * This is a small, fast and efficient software implementation of a 16-bit * Linear Feedback Shift Register (LFSR). It uses the Galois method to perform * the exclusive OR operations in parallel for improved performance over the - * standard, or Fibonacci, method. The algorithm also skips the exlusive or - * operations if it doesn't need to do them, though on this uC the branch may - * not generate a net performance increase over doing the exclusive or - * operations every time. - * - * After rng returns, RNGLO and RNGHI contain the updated 16-bit random number. - * RNGLO will contain a value $01-$FF, RNGHI will contain $00-$FF. + * standard, or Fibonacci, method. * * @author R. Steve McKown */