1/* ffsll -- find first set bit in a long long, from least significant end. 2 Copyright (C) 2013-2021 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library. If not, see 17 <https://www.gnu.org/licenses/>. */ 18 19#include <sysdep.h> 20 21 .syntax unified 22 .text 23 24ENTRY (ffsll) 25 @ If low part is 0, operate on the high part. Ensure that the 26 @ word on which we operate is in r0. Set r2 to the bit offset 27 @ of the word being considered. Set the flags for the word 28 @ being operated on. 29#ifdef __ARMEL__ 30 cmp r0, #0 31 itee ne 32 movne r2, #0 33 moveq r2, #32 34 movseq r0, r1 35#else 36 cmp r1, #0 37 ittee ne 38 movne r2, #0 39 movne r0, r1 40 moveq r2, #32 41 cmpeq r0, #0 42#endif 43 @ Perform the ffs on r0. 44 rbit r0, r0 45 ittt ne 46 clzne r0, r0 47 addne r2, r2, #1 48 addne r0, r0, r2 49 bx lr 50END (ffsll) 51