[Pgubook-readers] movl _start, %eax

[Shuaib]

I dissasemble the maximum program in chapter 3.
(objdump maximum -D) and I get this (only a part of
it):

08048074 <_start>:
 8048074:       bf 00 00 00 00          mov   
$0x0,%edi
 8048079:       8b 04 bd a8 90 04 08    mov
0x80490a8(,%edi,4),%eax

080490a8 <data_items>:
 80490a8:       07                      pop    %es
 80490a9:       00 00                   add   
%al,(%eax)
 80490ab:       00 08                   add   
%cl,(%eax)


When I try "movl _data_items, %eax", %eax has 7 in it.
When I try "movl $_data_items, %eax", %eax has
080490a8 in it. Great, everything makes sense!

On the other hand, When I try "movl $_start, %eax",
%eax has 08048074 in it (good; makes sense since
$_start is the address). When I try "movl _data_items,
%eax", %eax has 0xcc in it. The address location
pointed to by _start contains bf000000, and I was
expecting bf000000 when I executed that instruction.
WHY am I getting 0xcc? I suspect other people will get
other values in the %eax. 

Here is what I'd like some elite to clarify: Does the
OS (or the loader) relocate the _start section
somewhere else in the memory and 0x08048074 no longer
points to the the original address that _start pointed
to? Where does this 0xcc come from? Will I be able to
see this in the dissasembly section?

I'd very much appreciate an explanation. I do not
believe the reason is in the book.


                
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