ArmPkg/Library/CompilerIntrinsicsLib/Arm/ctzsi2.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2008-2010 Apple Inc. All rights reserved.
   4 #
   5 # All rights reserved. This program and the accompanying materials
   6 # are licensed and made available under the terms and conditions of the BSD License
   7 # which accompanies this distribution.  The full text of the license may be found at
   8 # http://opensource.org/licenses/bsd-license.php
   9 #
  10 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12 #
  13 #------------------------------------------------------------------------------
  14
  15         .text
  16         .align 2
  17         .globl ___ctzsi2
  18 ___ctzsi2:
  19         @ args = 0, pretend = 0, frame = 0
  20         @ frame_needed = 0, uses_anonymous_args = 0
  21         @ link register save eliminated.
  22         uxth    r3, r0
  23         cmp     r3, #0
  24         moveq   ip, #16
  25         movne   ip, #0
  26         @ lr needed for prologue
  27         mov     r0, r0, lsr ip
  28         tst     r0, #255
  29         movne   r3, #0
  30         moveq   r3, #8
  31         mov     r0, r0, lsr r3
  32         tst     r0, #15
  33         movne   r1, #0
  34         moveq   r1, #4
  35         add     r3, r3, ip
  36         mov     r0, r0, lsr r1
  37         tst     r0, #3
  38         movne   r2, #0
  39         moveq   r2, #2
  40         add     r3, r3, r1
  41         mov     r0, r0, lsr r2
  42         and     r0, r0, #3
  43         add     r2, r3, r2
  44         eor     r3, r0, #1
  45         mov     r0, r0, lsr #1
  46         ands    r3, r3, #1
  47         mvnne   r3, #0
  48         rsb     r0, r0, #2
  49         and     r0, r3, r0
  50         add     r0, r2, r0
  51         bx      lr