- Revert 49927 "Update to trunk" as it breaks KsStudio (again)

[reactos.git] / lib / sdk / crt / mem / i386 / memcpy_asm.s

diff --git a/lib/sdk/crt/mem/i386/memcpy_asm.s b/lib/sdk/crt/mem/i386/memcpy_asm.s
index e69de29..36a1a07 100644 (file)
--- a/lib/sdk/crt/mem/i386/memcpy_asm.s
+++ b/lib/sdk/crt/mem/i386/memcpy_asm.s
@@ -0,0 +1,114 @@
+/*
+ * void *memcpy (void *to, const void *from, size_t count)
+ *
+ * NOTE: This code is a duplicate of memmove function from memmove_asm.s
+ */
+
+.globl _memcpy
+
+_memcpy:
+       push    %ebp
+       mov     %esp,%ebp
+       
+       push    %esi
+       push    %edi
+       
+       mov     8(%ebp),%edi
+       mov     12(%ebp),%esi
+       mov     16(%ebp),%ecx
+       
+       cmp     %esi,%edi
+       jbe     .CopyUp
+       mov     %ecx,%eax
+       add     %esi,%eax
+       cmp     %eax,%edi
+       jb      .CopyDown
+       
+.CopyUp:       
+       cld
+       
+       cmp     $16,%ecx
+       jb      .L1
+       mov     %ecx,%edx
+       test    $3,%edi
+       je      .L2
+/*
+ * Make the destination dword aligned
+ */
+        mov    %edi,%ecx
+        and    $3,%ecx
+        sub    $5,%ecx
+        not    %ecx
+        sub    %ecx,%edx
+        rep    movsb
+        mov    %edx,%ecx       
+.L2:
+       shr     $2,%ecx
+       rep     movsl
+       mov     %edx,%ecx
+       and     $3,%ecx
+.L1:   
+       test    %ecx,%ecx
+       je      .L3
+       rep     movsb
+.L3:
+       mov     8(%ebp),%eax
+       pop     %edi
+       pop     %esi
+       leave
+       ret
+
+.CopyDown:
+        std
+        
+       add     %ecx,%edi
+       add     %ecx,%esi
+       
+       cmp     $16,%ecx
+       jb      .L4
+        mov    %ecx,%edx
+       test    $3,%edi
+       je      .L5
+       
+/*
+ * Make the destination dword aligned
+ */
+       mov     %edi,%ecx
+       and     $3,%ecx
+       sub     %ecx,%edx
+       dec     %esi
+       dec     %edi
+       rep     movsb
+       mov     %edx,%ecx
+       
+       sub     $3,%esi
+       sub     $3,%edi
+.L6:   
+       shr     $2,%ecx
+       rep     movsl
+       mov     %edx,%ecx
+       and     $3,%ecx
+       je      .L7
+       add     $3,%esi
+       add     $3,%edi
+.L8:   
+       rep     movsb
+.L7:
+       cld
+       mov     8(%ebp),%eax
+       pop     %edi
+       pop     %esi
+       leave
+       ret
+.L5:
+       sub     $4,%edi
+       sub     $4,%esi
+       jmp     .L6
+               
+.L4:
+       test    %ecx,%ecx
+       je      .L7     
+       dec     %esi
+       dec     %edi
+       jmp     .L8
+