Re: Displacement def in as

If you are using the gnu assembler, gas, you should
become familiar with the info for it. The command
is
    info as

Go to Machine Dependencies, then i386-Dependent,
then i386-Memory. There you will see that the AT&T
syntax is
    DISP(BASE, INDEX, SCALE)

DISP is an integer. An example is
    movl   $0, -4(%ebp)
which would store 32 bits of zero at the
memory location starting 4 bytes negative
from the address in the ebp register. (This
instruction does not use INDEX or SCALE.)

Linux uses a flat memory model, so you don't
need to worry about the segmentation registers
if you run your program under Linux.


On Wed, 2006-11-22 at 18:44 -0500, A D wrote:
> I am a newbie and i have question. What does
> displacement mean according to segmented
> memory model? Does it mean anything  in terms
> of Segment Descriptor? Thanks.
> 
> Offset = Base + (Index * Scale) + displacement
> 


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