/* * Utility functions * * Copyright (c) 2015 Michael Buesch * * 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., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "util.h" int32_t pow_int(int16_t b, uint8_t e) { int32_t x, y; if (!e) return 1; x = b; while (!(e & 1)) { e = (uint8_t)(e >> 1); x *= x; } y = x; e = (uint8_t)(e >> 1); while (e) { x *= x; if (e & 1) y *= x; e = (uint8_t)(e >> 1); } return y; }