1*ae3cb403Sguenther/* $OpenBSD: ffs.S,v 1.5 2018/01/18 08:23:44 guenther Exp $ */ 20eea0d08Spefo/*- 30eea0d08Spefo * Copyright (c) 1991, 1993 40eea0d08Spefo * The Regents of the University of California. All rights reserved. 50eea0d08Spefo * 60eea0d08Spefo * This code is derived from software contributed to Berkeley by 70eea0d08Spefo * Ralph Campbell. 80eea0d08Spefo * 90eea0d08Spefo * Redistribution and use in source and binary forms, with or without 100eea0d08Spefo * modification, are permitted provided that the following conditions 110eea0d08Spefo * are met: 120eea0d08Spefo * 1. Redistributions of source code must retain the above copyright 130eea0d08Spefo * notice, this list of conditions and the following disclaimer. 140eea0d08Spefo * 2. Redistributions in binary form must reproduce the above copyright 150eea0d08Spefo * notice, this list of conditions and the following disclaimer in the 160eea0d08Spefo * documentation and/or other materials provided with the distribution. 170eea0d08Spefo * 3. Neither the name of the University nor the names of its contributors 180eea0d08Spefo * may be used to endorse or promote products derived from this software 190eea0d08Spefo * without specific prior written permission. 200eea0d08Spefo * 210eea0d08Spefo * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 220eea0d08Spefo * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 230eea0d08Spefo * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 240eea0d08Spefo * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 250eea0d08Spefo * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 260eea0d08Spefo * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 270eea0d08Spefo * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 280eea0d08Spefo * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 290eea0d08Spefo * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 300eea0d08Spefo * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 310eea0d08Spefo * SUCH DAMAGE. 320eea0d08Spefo */ 330eea0d08Spefo 349b9d2a55Sguenther#include "SYS.h" 350eea0d08Spefo 360eea0d08Spefo/* bit = ffs(value) */ 370eea0d08Spefo 385738bc62SpefoLEAF(ffs, 0) 390eea0d08Spefo .set reorder 400eea0d08Spefo move v0, zero 410eea0d08Spefo beq a0, zero, done 420eea0d08Spefo1: 430eea0d08Spefo and v1, a0, 1 # bit set? 440eea0d08Spefo addu v0, v0, 1 450eea0d08Spefo srl a0, a0, 1 460eea0d08Spefo beq v1, zero, 1b # no, continue 470eea0d08Spefodone: 480eea0d08Spefo j ra 49*ae3cb403SguentherEND(ffs) 50*ae3cb403Sguenther.protected ffs 51