| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame] | 1 | /* $NetBSD: ffs.S,v 1.5 2003/04/05 23:08:52 bjh21 Exp $ */ |
| 2 | /* |
| 3 | * Copyright (c) 2001 Christopher Gilbert |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions |
| 8 | * are met: |
| 9 | * 1. Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * 3. The name of the company nor the name of the author may be used to |
| 15 | * endorse or promote products derived from this software without specific |
| 16 | * prior written permission. |
| 17 | * |
| 18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 20 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 21 | * IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, |
| 22 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 23 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| 24 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 25 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 26 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 27 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 28 | * SUCH DAMAGE. |
| 29 | */ |
| 30 | |
| 31 | #include <machine/asm.h> |
| Kenny Root | 0233509 | 2011-02-17 07:50:36 -0800 | [diff] [blame] | 32 | #include <machine/cpu-features.h> |
| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame] | 33 | |
| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame] | 34 | ENTRY(ffs) |
| 35 | /* Standard trick to isolate bottom bit in r0 or 0 if r0 = 0 on entry */ |
| 36 | rsb r1, r0, #0 |
| 37 | ands r0, r0, r1 |
| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame] | 38 | clzne r0, r0 |
| 39 | rsbne r0, r0, #32 |
| 40 | bx lr |
| Kenny Root | 420878c | 2011-02-16 11:55:58 -0800 | [diff] [blame] | 41 | END(ffs) |