ArmPkg/Library/CompilerIntrinsicsLib/Arm/ctzsi2.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
   4 #
   5 # 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 ASM_PFX(__ctzsi2)
  18   INTERWORK_FUNC(__ctzsi2)
  19
  20 ASM_PFX(__ctzsi2):
  21         uxth    r3, r0
  22         cmp     r3, #0
  23         moveq   ip, #16
  24         movne   ip, #0
  25         @ lr needed for prologue
  26         mov     r0, r0, lsr ip
  27         tst     r0, #255
  28         movne   r3, #0
  29         moveq   r3, #8
  30         mov     r0, r0, lsr r3
  31         tst     r0, #15
  32         movne   r1, #0
  33         moveq   r1, #4
  34         add     r3, r3, ip
  35         mov     r0, r0, lsr r1
  36         tst     r0, #3
  37         movne   r2, #0
  38         moveq   r2, #2
  39         add     r3, r3, r1
  40         mov     r0, r0, lsr r2
  41         and     r0, r0, #3
  42         add     r2, r3, r2
  43         eor     r3, r0, #1
  44         mov     r0, r0, lsr #1
  45         ands    r3, r3, #1
  46         mvnne   r3, #0
  47         rsb     r0, r0, #2
  48         and     r0, r3, r0
  49         add     r0, r2, r0
  50         bx      lr