ArmPkg/Library/BaseMemoryLibVstm/Arm/CopyMem.asm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; CopyMem() worker for ARM
   4 ;
   5 ; This file started out as C code that did 64 bit moves if the buffer was
   6 ; 32-bit aligned, else it does a byte copy. It also does a byte copy for
   7 ; any trailing bytes. Update using VSTM/SLDM to do 128 byte copies.
   8 ;
   9 ; Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
  10 ; This program and the accompanying materials
  11 ; are licensed and made available under the terms and conditions of the BSD License
  12 ; which accompanies this distribution.  The full text of the license may be found at
  13 ; http://opensource.org/licenses/bsd-license.php
  14 ;
  15 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  16 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  17 ;
  18 ;------------------------------------------------------------------------------
  19
  20 /**
  21   Copy Length bytes from Source to Destination. Overlap is OK.
  22
  23   This implementation
  24
  25   @param  Destination Target of copy
  26   @param  Source      Place to copy from
  27   @param  Length      Number of bytes to copy
  28
  29   @return Destination
  30
  31
  32 VOID *
  33 EFIAPI
  34 InternalMemCopyMem (
  35   OUT     VOID                      *DestinationBuffer,
  36   IN      CONST VOID                *SourceBuffer,
  37   IN      UINTN                     Length
  38   )
  39 **/
  40
  41     INCLUDE AsmMacroExport.inc
  42
  43  RVCT_ASM_EXPORT InternalMemCopyMem
  44   stmfd  sp!, {r4, r9, lr}
  45   tst  r0, #3
  46   mov  r4, r0
  47   mov  r9, r0
  48   mov  ip, r2
  49   mov  lr, r1
  50   movne  r0, #0
  51   bne  L4
  52   tst  r1, #3
  53   movne  r3, #0
  54   moveq  r3, #1
  55   cmp  r2, #127
  56   movls  r0, #0
  57   andhi  r0, r3, #1
  58 L4
  59   cmp  r4, r1
  60   bcc  L26
  61   bls  L7
  62   rsb  r3, r1, r4
  63   cmp  ip, r3
  64   bcc  L26
  65   cmp  ip, #0
  66   beq  L7
  67   add  r9, r4, ip
  68   add  lr, ip, r1
  69   b  L16
  70 L29
  71   sub  ip, ip, #8
  72   cmp  ip, #7
  73   ldrd  r2, [lr, #-8]!
  74   movls  r0, #0
  75   cmp  ip, #0
  76   strd  r2, [r9, #-8]!
  77   beq  L7
  78 L16
  79   cmp  r0, #0
  80   bne  L29
  81   sub  r3, lr, #1
  82   sub  ip, ip, #1
  83   ldrb  r3, [r3, #0]
  84   sub  r2, r9, #1
  85   cmp  ip, #0
  86   sub  r9, r9, #1
  87   sub  lr, lr, #1
  88   strb  r3, [r2, #0]
  89   bne  L16
  90   b   L7
  91 L11
  92   ldrb  r3, [lr], #1
  93   sub  ip, ip, #1
  94   strb  r3, [r9], #1
  95 L26
  96   cmp  ip, #0
  97   beq  L7
  98 L30
  99   cmp  r0, #0
 100   beq  L11
 101   sub  ip, ip, #128          // 32
 102   cmp  ip, #127              // 31
 103   vldm     lr!, {d0-d15}
 104   movls  r0, #0
 105   cmp  ip, #0
 106   vstm  r9!, {d0-d15}
 107   bne  L30
 108 L7
 109   dsb
 110   mov  r0, r4
 111   ldmfd  sp!, {r4, r9, pc}
 112
 113   END
 114