ppc/string/ffs.s

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