ppc/gen/ffs.s

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /* Copyright (c) 1992, 1997 NeXT Software, Inc.  All rights reserved.
  26  *
  27  *      File:  libc/gen/ppc/ffs.s
  28  *
  29  *      Find the first bit set (starting with the least significant bit).
  30  *
  31  * HISTORY
  32  *
  33  *  24-Jan-1997 Umesh Vaishampayan (umeshv@NeXT.com)
  34  *      Ported to PPC.
  35  *
  36  *  19-Jan-1998 Matt Watson (mwatson@apple.com)
  37  *      Simplified
  38  *
  39  *  10-Mar-1998 Matt Watson (mwatson@apple.com)
  40  *      Correctified
  41  *
  42  */
  43
  44 .text
  45 .align 2
  46 .globl _ffs
  47 _ffs:
  48         neg    r0,r3
  49         and    r3,r0,r3
  50         cntlzw r3,r3
  51         subfic r3,r3,32
  52         blr