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Re: basic system call question
On Mon, May 14, 2001 at 08:51:07AM +0100, Ralph Corderoy wrote:
> > Why is the syscall "int 0x80"? Is this where the system is actually
> > executed with the arguments previously listed? It is not the return
> > value, and the system call number is already 42.
>
> The `int 0x80' generates the interrupt that switches to the kernel
> which in turn seems to examine the %eax register to see what system
> call is required. I'd guess all system calls generate the same
> interrupt, 0x80, and the only thing to distuinguish between them is the
> value of %eax.
Your guess is correct (for i386, that is ;).
Erik
--
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031, 2600 GA Delft, The Netherlands
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WWW: http://www-ict.its.tudelft.nl/~erik/
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