ebp register in i386

I see in i386/unified.S the lines:

	push	%ebp
	movl	10*4(%edi),%ebp
	pop	%ebp

What about if we remove above lines and change:
-	 movl	5*4(%edi),%ebx
-	 movl	6*4(%edi),%ecx
-	 movl	7*4(%edi),%edx
-	 movl	8*4(%edi),%esi
-	 movl	9*4(%edi),%edi

+	 movl	4*4(%edi),%ebx
+	 movl	5*4(%edi),%ecx
+	 movl	6*4(%edi),%edx
+	 movl	7*4(%edi),%esi
+	 movl	8*4(%edi),%edi

As I understand syscalls does not modify %ebp and with the above
changes all should be OK.  Maybe for some reason %ebp
is in unified.S (save, restore)?  Any help is welcome!

/nv