/* fixed_sqrt_ui32.c */ /* avr.math.fixed - Fixed point math module. {{{ * * Copyright (C) 2005 Nicolas Schodet * * Robot APB Team/Efrei 2006. * Web: http://assos.efrei.fr/robot/ * Email: robot AT efrei DOT fr * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * }}} */ #include "common.h" #include "fixed.h" /** Compute square root, ui32 -> ui16. */ uint16_t fixed_sqrt_ui32 (uint32_t x) { uint32_t root, bit, test; root = 0; bit = 1L << 30; do { test = root + bit; if (x >= test) { x -= test; root = test + bit; } root >>= 1; bit >>= 2; } while (bit); return root; }