string.s

   1 format ELF
   2
   3 public memcpy
   4 memcpy:
   5         push    esi
   6         push    edi
   7         mov     edi, [esp+12]
   8         mov     esi, [esp+16]
   9         mov     ecx, [esp+20]
  10         mov     eax, edi
  11         cld
  12         rep movsb
  13         pop     edi
  14         pop     esi
  15         ret
  16
  17 public memmove
  18 memmove:
  19         push    esi
  20         push    edi
  21         mov     edi, [esp+12]
  22         mov     esi, [esp+16]
  23         mov     ecx, [esp+20]
  24         cmp     edi, esi
  25         jng     .usual
  26         mov     eax, esi
  27         add     eax, ecx
  28         cmp     edi, eax
  29         jg      .usual
  30
  31         mov     eax, edi
  32         std
  33         add     esi, ecx
  34         add     edi, ecx
  35         dec     esi
  36         dec     edi
  37         rep movsb
  38         jmp     .ret
  39 .usual:
  40         mov     eax, edi
  41         cld
  42         rep movsb
  43 .ret:
  44         pop     edi
  45         pop     esi
  46         ret
  47
  48 public memset
  49 memset:
  50         push    edi
  51         mov     edi, [esp+8]
  52         mov     eax, [esp+12]
  53         mov     ecx, [esp+16]
  54         mov     edx, edi
  55         cld
  56         rep stosb
  57         pop     edi
  58         mov     eax, edx
  59         ret
  60
  61 public memchr
  62 memchr:
  63         mov     eax, [esp+8]
  64         mov     ecx, [esp+12]
  65         push    edi
  66         mov     edi, [esp+8]
  67         cld
  68         repnz scasb
  69         jne     .failed
  70         mov     eax, edi
  71         dec     eax
  72         jmp     .ret
  73 .failed:
  74         xor     eax, eax
  75 .ret:
  76         pop     edi
  77         ret
  78
  79 public memcmp
  80 memcmp:
  81         push    esi
  82         push    edi
  83         xor     eax, eax
  84         mov     esi, [esp+12]
  85         mov     edi, [esp+16]
  86         mov     ecx, [esp+20]
  87         jecxz   .ret
  88
  89         cld
  90         rep cmpsb
  91         jz      .ret
  92         sbb     eax, eax
  93         or      eax, 1
  94 .ret:
  95         pop     edi
  96         pop     esi
  97         ret
  98
  99 public strlen
 100 strlen:
 101         push    edi
 102         mov     edi, [esp+8]
 103         xor     eax, eax
 104         mov     ecx, -1
 105         cld
 106         repnz scasb
 107         mov     eax, ecx
 108         not     eax
 109         dec     eax
 110         pop     edi
 111         ret
 112
 113 public memrchr
 114 memrchr:
 115         mov     eax, [esp+8]
 116         mov     ecx, [esp+12]
 117         push    edi
 118         mov     edi, [esp+8]
 119         add     edi, ecx
 120         dec     edi
 121         std
 122         repnz scasb
 123         jne     .failed
 124         mov     eax, edi
 125         inc     eax
 126         jmp     .ret
 127 .failed:
 128         xor     eax, eax
 129 .ret:
 130         pop     edi
 131         ret
 132
 133 public strchr
 134 strchr:
 135         mov     ecx, [esp+4]
 136         mov     edx, [esp+8]
 137 .loop:
 138         mov     al, [ecx]
 139         cmp     al, dl
 140         jz      .done
 141         inc     ecx
 142         test    al, al
 143         jnz     .loop
 144         xor     ecx, ecx
 145 .done:
 146         mov     eax, ecx
 147         ret
 148
 149 public strcmp
 150 strcmp:
 151         mov     ecx, [esp+4]
 152         mov     edx, [esp+8]
 153         xor     eax, eax
 154 .loop:
 155         mov     al, [ecx]
 156         cmp     al, [edx]
 157         jnz     .ret
 158         inc     edx
 159         inc     ecx
 160         test    al, al
 161         jnz     .loop
 162         ret
 163 .ret:
 164         movzx   ecx, byte [edx]
 165         sub     eax, ecx
 166         ret
 167
 168 public strcpy
 169 strcpy:
 170         push    edi
 171         push    esi
 172         mov     edx, [esp+12]
 173         mov     esi, [esp+16]
 174         mov     edi, edx
 175         cld
 176 .loop:
 177         lodsb
 178         stosb
 179         or      al, al
 180         jnz     .loop
 181         pop     esi
 182         pop     edi
 183         mov     eax, edx
 184         ret
 185
 186 public strrchr
 187 strrchr:
 188         push    edi
 189         mov     edi, [esp+8]
 190         mov     ecx, [esp+12]
 191         xor     edx, edx
 192         dec     edi
 193 .loop:
 194         inc     edi
 195         test    al, al
 196         jz      .done
 197         mov     al, [edi]
 198         cmp     al, cl
 199         jnz     .loop
 200         mov     edx, edi
 201         jz      .loop
 202 .done:
 203         mov     eax, edx
 204         pop     edi
 205         ret