ArmPkg/Library/CompilerIntrinsicsLib/Arm/ctzsi2.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
   4 #
   5 # SPDX-License-Identifier: BSD-2-Clause-Patent
   6 #
   7 #------------------------------------------------------------------------------
   8
   9 #include <AsmMacroIoLib.h>
  10
  11 ASM_FUNC(__ctzsi2)
  12   uxth  r3, r0
  13   cmp  r3, #0
  14   moveq  ip, #16
  15   movne  ip, #0
  16   @ lr needed for prologue
  17   mov  r0, r0, lsr ip
  18   tst  r0, #255
  19   movne  r3, #0
  20   moveq  r3, #8
  21   mov  r0, r0, lsr r3
  22   tst  r0, #15
  23   movne  r1, #0
  24   moveq  r1, #4
  25   add  r3, r3, ip
  26   mov  r0, r0, lsr r1
  27   tst  r0, #3
  28   movne  r2, #0
  29   moveq  r2, #2
  30   add  r3, r3, r1
  31   mov  r0, r0, lsr r2
  32   and  r0, r0, #3
  33   add  r2, r3, r2
  34   eor  r3, r0, #1
  35   mov  r0, r0, lsr #1
  36   ands  r3, r3, #1
  37   mvnne  r3, #0
  38   rsb  r0, r0, #2
  39   and  r0, r3, r0
  40   add  r0, r2, r0
  41   bx  lr