1/* $OpenBSD: ffs.S,v 1.1 2020/06/10 20:19:29 naddy Exp $ */ 2/* 3 * Written by Christian Weisgerber <naddy@openbsd.org>. 4 * Public domain. 5 */ 6 7#include <machine/asm.h> 8 9ENTRY(ffs) 10 RETGUARD_SETUP(ffs, x15) 11 rbit w1, w0 12 clz w1, w1 13 cmp w0, wzr 14 csinc w0, wzr, w1, eq 15 RETGUARD_CHECK(ffs, x15) 16 ret 17END(ffs) 18