string.s

   1 format ELF
   2
   3 public memcpy
   4 public memmove
   5 memcpy:
   6 memmove:
   7         push    esi
   8         push    edi
   9         mov     edi, [esp+12]
  10         mov     esi, [esp+16]
  11         mov     ecx, [esp+20]
  12         mov     eax, edi
  13         cld
  14         rep movsb
  15         pop     edi
  16         pop     esi
  17         ret
  18
  19 public memset
  20 memset:
  21         push    edi
  22         mov     edi, [esp+8]
  23         mov     eax, [esp+12]
  24         mov     ecx, [esp+16]
  25         mov     edx, edi
  26         cld
  27         rep stosb
  28         pop     edi
  29         mov     eax, edx
  30         ret
  31
  32 public memchr
  33 memchr:
  34         mov     eax, [esp+8]
  35         mov     ecx, [esp+12]
  36         push    edi
  37         mov     edi, [esp+8]
  38         cld
  39         repnz scasb
  40         jne     .failed
  41         mov     eax, edi
  42         dec     eax
  43         jmp     .ret
  44 .failed:
  45         xor     eax, eax
  46 .ret:
  47         pop     edi
  48         ret
  49
  50 public strlen
  51 strlen:
  52         push    edi
  53         mov     edi, [esp+8]
  54         xor     eax, eax
  55         mov     ecx, -1
  56         cld
  57         repnz scasb
  58         mov     eax, ecx
  59         not     eax
  60         dec     eax
  61         pop     edi
  62         ret
  63
  64 public strchr
  65 strchr:
  66         mov     ecx, [esp+4]
  67         mov     edx, [esp+8]
  68 .loop:
  69         mov     al, [ecx]
  70         cmp     al, dl
  71         jz      .done
  72         inc     ecx
  73         test    al, al
  74         jnz     .loop
  75         xor     ecx, ecx
  76 .done:
  77         mov     eax, ecx
  78         ret
  79
  80 public strcmp
  81 strcmp:
  82         mov     ecx, [esp+4]
  83         mov     edx, [esp+8]
  84         xor     eax, eax
  85 .loop:
  86         mov     al, [ecx]
  87         cmp     al, [edx]
  88         jnz     .ret
  89         inc     edx
  90         inc     ecx
  91         test    al, al
  92         jnz     .loop
  93         ret
  94 .ret:
  95         movzx   ecx, byte [edx]
  96         sub     eax, ecx
  97         ret
  98
  99 public strcpy
 100 strcpy:
 101         push    edi
 102         push    esi
 103         mov     edx, [esp+12]
 104         mov     esi, [esp+16]
 105         mov     edi, edx
 106         cld
 107 .loop:
 108         lodsb
 109         stosb
 110         or      al, al
 111         jnz     .loop
 112         pop     edi
 113         pop     esi
 114         mov     eax, edx
 115         ret