update for HEAD-2003091401

[reactos.git] / lib / ntdll / nasm / rtl / i386_RtlCompareMemory.asm

diff --git a/lib/ntdll/nasm/rtl/i386_RtlCompareMemory.asm b/lib/ntdll/nasm/rtl/i386_RtlCompareMemory.asm
new file mode 100644 (file)
index 0000000..f00011a
--- /dev/null
+++ b/lib/ntdll/nasm/rtl/i386_RtlCompareMemory.asm
@@ -0,0 +1,49 @@
+; * base on ntdll/rtl/mem.c v 1.13 2003/07/11 13:50:23 
+; * 
+; * COPYRIGHT:       See COPYING in the top level directory
+; * PROJECT:         ReactOS kernel
+; * FILE:            i386_RtlCompareMemory.asm
+; * PURPOSE:         Memory functions
+; * PROGRAMMER:      Magnus Olsen (magnusolsen@greatlord.com)
+; * UPDATE HISTORY:
+; *                  Created 20/07-2003
+; * 
+                        
+  
+
+
+         BITS 32
+        GLOBAL _RtlCompareMemory@12      ; [4]  (no bug)  
+        
+        SECTION .text
+
+; *
+; * [4] ULONG STDCALL RtlCompareMemory(PVOID Source1, PVOID Source2, ULONG Length)
+; *
+
+_RtlCompareMemory@12:
+      xor eax,eax                    ; count = 0  
+      mov ecx, dword [esp + 12 ]     ; ecx = Length                                       
+       cmp ecx,0                      ; if (Length==0) goto .zero
+       je  .zero
+      
+      push edi                       ; register that does not to be save eax,ecx,edx to 
+      push ebx                       ; the stack for protetion
+                            
+      mov edi, dword [esp + (4 + 8)] ; edi = Destination                       
+      mov edx, dword [esp + (8 + 8)] ; edx = Source                         
+
+.loop_1byte:
+      mov bl,byte [edi + eax ]      ;  if (src[count]!=des[count]) goto .pop_zero           
+      cmp byte [edx + eax ],bl      
+      jne .pop_zero                 
+
+      inc eax                       ;  count = count + 1
+      dec ecx                       ;  Length = Length - 1
+      jnz .loop_1byte               ;  if (Length!=0) goto .loop_1byte
+
+.pop_zero:      
+      pop ebx                       ; restore regiester 
+      pop edi                       
+.zero:   
+      ret 12                        ; return count