i386: far jumps

[Emanuele Altieri <ealtieri@hampshire.edu>]

Greetings,

I'm doing some experiments with far jumps to different code segments.
For example:

   ljmp $16, $hello

where $16 is the segment selector, and "hello" is a label that I set up
for testing. The code above works fine.

However, when I change the code as following:

   movw $16, %dx
   movw %dx, %fs
   ljmp *%fs:hello

I get a general protection error. I don't understand why. I believe it's
a notation error. Can anybody see it?

I'm interested in this because I need the segment argument of ljmp to be
variable.


Thanks!


 -Emanuele