ArmPkg/Library/CompilerIntrinsicsLib/Arm/memmove.asm

   1 //------------------------------------------------------------------------------
   2 //
   3 // Copyright (c) 2011, ARM Limited. All rights reserved.
   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
  16     EXPORT  __aeabi_memmove
  17
  18     AREA    Memmove, CODE, READONLY
  19
  20 ;
  21 ;VOID
  22 ;EFIAPI
  23 ;__aeabi_memmove (
  24 ; IN  VOID          *Destination,
  25 ; IN  CONST VOID    *Source,
  26 ; IN  UINT32        Size
  27 ; );
  28 ;
  29 __aeabi_memmove
  30   CMP     r2, #0
  31   BXEQ    r14
  32   CMP     r0, r1
  33   BXEQ    r14
  34   BHI     memmove_backward
  35   BLS     memmove_forward
  36
  37 memmove_forward
  38   LDRB    r3, [r1], #1
  39   STRB    r3, [r0], #1
  40   SUBS    r2, r2, #1
  41   BXEQ    r14
  42   B       memmove_forward
  43
  44 memmove_backward
  45   add     r0, r2
  46   add     r1, r2
  47 memmove_backward_loop
  48   LDRB    r3, [r1], #-1
  49   STRB    r3, [r0], #-1
  50   SUBS    r2, r2, #-1
  51   BXEQ    r14
  52   B       memmove_backward_loop
  53
  54   END