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