Re: A newbie's question

DervishD (raul@pleyades.net)
Thu, 26 Sep 2002 18:14:24 +0200


Hi unknown :)

> rep
> movw

In my bootsector.S, it's movsw: repeat move (string) by words.
'movw' is 'mov word size operands'.

> jmpi go,INITSEG

AFAIK, the correct is 'ljmp': long jump. What kernel sources are
you seeing?. Old kernels (2.0 and I think that 2.2 too) used as86 to
do the assembling, and the syntax was like the Intel one, but with
some differences. Not quite standard, I think.

> /////////////////////////////
> 1. What assembly language used in boot.s? Intel Asm or AT&T?

AT&T in new kernels, fully 'assembleable' with GNU as. IMHO is a
better syntax, but I don't want to feed a troll here ;)

> 2. Where is the definition of operand movw and jmpi?
> I cant find it in the Intel Manual.

Of course, there aren't Intel syntax anyway :) I recommend you to
see the 2.4 sources for reading the assembler part. Moreover, the
info section for 'GNU as' comments the differences between Intel
assembly syntax and the AT&T one. This will be of great help.

In addition to this, I have a document about using GNU as for
real mode assembly that comments some of these points. But it is
written in spanish only :((

Last, the Assembly-HOWTO will cast some light to the issue, too.

Raśl
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