reactos/lib/string/i386/memcpy_asm.s

   1 /*
   2  * void *memcpy (void *to, const void *from, size_t count)
   3  *
   4  * Some optimization research can be found in media/doc/memcpy_optimize.txt
   5  */
   6
   7 .globl  _memcpy
   8
   9 _memcpy:
  10         push    %ebp
  11         mov     %esp,%ebp
  12         push    %esi
  13         push    %edi
  14         mov     0x8(%ebp),%edi
  15         mov     0xc(%ebp),%esi
  16         mov     0x10(%ebp),%ecx
  17         cld
  18         cmp     $16,%ecx
  19         jb      .L1
  20         mov     %ecx,%edx
  21         test    $3,%edi
  22         je      .L2
  23 /*
  24  *  Make the destination dword aligned
  25  */
  26         mov     %edi,%ecx
  27         and     $3,%ecx
  28         sub     $5,%ecx
  29         not     %ecx
  30         sub     %ecx,%edx
  31         rep     movsb
  32         mov     %edx,%ecx
  33 .L2:
  34         shr     $2,%ecx
  35         rep     movsl
  36         mov     %edx,%ecx
  37         and     $3,%ecx
  38 .L1:
  39         test    %ecx,%ecx
  40         je      .L3
  41         rep     movsb
  42 .L3:
  43         pop     %edi
  44         pop     %esi
  45         mov     0x8(%ebp),%eax
  46         leave
  47         ret
  48