ArmPkg/Library/BaseMemoryLibStm/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. It was updated to do 32-byte copies using stm/ldm.
   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 \s\sEXPORT InternalMemCopyMem
  41
  42 \s\sAREA AsmMemStuff, CODE, READONLY
  43
  44 InternalMemCopyMem
  45 \s\sstmfd\s\ssp!, {r4-r11, lr}
  46 \s\stst\s\sr0, #3
  47 \s\smov\s\sr11, r0
  48 \s\smov\s\sr10, r0
  49 \s\smov\s\sip, r2
  50 \s\smov\s\slr, r1
  51 \s\smovne\s\sr0, #0
  52 \s\sbne\s\sL4
  53 \s\stst\s\sr1, #3
  54 \s\smovne\s\sr3, #0
  55 \s\smoveq\s\sr3, #1
  56 \s\scmp\s\sr2, #31
  57 \s\smovls\s\sr0, #0
  58 \s\sandhi\s\sr0, r3, #1
  59 L4
  60 \s\scmp\s\sr11, r1
  61 \s\sbcc\s\sL26
  62 \s\sbls\s\sL7
  63 \s\srsb\s\sr3, r1, r11
  64 \s\scmp\s\sip, r3
  65 \s\sbcc\s\sL26
  66 \s\scmp\s\sip, #0
  67 \s\sbeq\s\sL7
  68 \s\sadd\s\sr10, r11, ip
  69 \s\sadd\s\slr, ip, r1
  70 \s\sb\s\sL16
  71 L29
  72 \s\ssub\s\sip, ip, #8
  73 \s\scmp\s\sip, #7
  74 \s\sldrd\s\sr2, [lr, #-8]!
  75 \s\smovls\s\sr0, #0
  76 \s\scmp\s\sip, #0
  77 \s\sstrd\s\sr2, [r10, #-8]!
  78 \s\sbeq\s\sL7
  79 L16
  80 \s\scmp\s\sr0, #0
  81 \s\sbne\s\sL29
  82 \s\ssub\s\sr3, lr, #1
  83 \s\ssub\s\sip, ip, #1
  84 \s\sldrb\s\sr3, [r3, #0]\s\s
  85 \s\ssub\s\sr2, r10, #1
  86 \s\scmp\s\sip, #0
  87 \s\ssub\s\sr10, r10, #1
  88 \s\ssub\s\slr, lr, #1
  89 \s\sstrb\s\sr3, [r2, #0]
  90 \s\sbne\s\sL16
  91 \s\sb   L7
  92 L11
  93 \s\sldrb\s\sr3, [lr], #1\s\s
  94 \s\ssub\s\sip, ip, #1
  95 \s\sstrb\s\sr3, [r10], #1
  96 L26
  97 \s\scmp\s\sip, #0
  98 \s\sbeq\s\sL7
  99 L30
 100 \s\scmp\s\sr0, #0
 101 \s\sbeq\s\sL11
 102 \s\ssub\s\sip, ip, #32
 103 \s\scmp\s\sip, #31
 104 \s\sldmia\s\slr!, {r2-r9}
 105 \s\smovls\s\sr0, #0
 106 \s\scmp\s\sip, #0
 107 \s\sstmia\s\sr10!, {r2-r9}
 108 \s\sbne\s\sL30
 109 L7
 110   mov\s\sr0, r11
 111 \s\sldmfd\s\ssp!, {r4-r11, pc}
 112 \s\s
 113   END
 114