ArmPkg/Library/CompilerIntrinsicsLib/Arm/clzsi2.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 #include <AsmMacroIoLib.h>
  16
  17 ASM_FUNC(__clzsi2)
  18   @ frame_needed = 1, uses_anonymous_args = 0
  19   stmfd  sp!, {r7, lr}
  20   add  r7, sp, #0
  21   movs  r3, r0, lsr #16
  22   movne  r3, #16
  23   moveq  r3, #0
  24   movne  r9, #0
  25   moveq  r9, #16
  26   mov  r3, r0, lsr r3
  27   tst  r3, #65280
  28   movne  r0, #8
  29   moveq  r0, #0
  30   movne  lr, #0
  31   moveq  lr, #8
  32   mov  r3, r3, lsr r0
  33   tst  r3, #240
  34   movne  r0, #4
  35   moveq  r0, #0
  36   movne  ip, #0
  37   moveq  ip, #4
  38   mov  r3, r3, lsr r0
  39   tst  r3, #12
  40   movne  r0, #2
  41   moveq  r0, #0
  42   movne  r1, #0
  43   moveq  r1, #2
  44   mov  r2, r3, lsr r0
  45   add  r3, lr, r9
  46   add  r0, r3, ip
  47   add  r1, r0, r1
  48   mov  r0, r2, lsr #1
  49   eor  r0, r0, #1
  50   ands  r0, r0, #1
  51   mvnne  r0, #0
  52   rsb  r3, r2, #2
  53   and  r0, r0, r3
  54   add  r0, r1, r0
  55   ldmfd  sp!, {r7, pc}