nasm-users

[Nasm-users] multisection example...

[Jacques M. <jac...@gm...>]

Hi,

 Can anyone give me an example of how to use section.<secname>.start?

 I tried this:

------ test.asm -------

section mysection

mysectionsize equ $ - section.mysection.start
--------------------------

This will tell me section.mysection.start wasn't defined prior to its use..=
.

What's wrong?

Thanks!

Jacques Mony (V2_OS project)

Re: [Nasm-users] multisection example...

[Frank K. <fbk...@co...>]

Jacques Mony wrote:
> Hi,
> 
>  Can anyone give me an example of how to use section.<secname>.start?
> 
>  I tried this:
> 
> ------ test.asm -------
> 
> section mysection
> 
> mysectionsize equ $ - section.mysection.start
> --------------------------
> 
> This will tell me section.mysection.start wasn't defined prior to its use...
> 
> What's wrong?

Dunno. I can confirm that it happens. I *think* you're doing everything 
right. If I add the "-O" switch, the error message changes to "invalid 
operand type". I suspect a bug. I'll pass this on to the developer's 
list, and see if anyone has any ideas...

Thanks for testing the multisection support and letting us know!

Best,
Frank

Re: [Nasm-devel] Re: [Nasm-users] multisection example...

[anonymous c. <nas...@ya...>]

Frank,
> > section mysection
> > mysectionsize equ $ - section.mysection.start
> > 
> > This will tell me section.mysection.start wasn't defined prior to its use...
> > 
> > What's wrong?
> 
> Dunno. I can confirm that it happens. I *think* you're doing everything 
> right. If I add the "-O" switch, the error message changes to "invalid 
> operand type". I suspect a bug. I'll pass this on to the developer's 
> list, and see if anyone has any ideas...

The section.<name>.start label is defined by bin_define_section_labels()
in outbin.c. However, that function isn't called until after the second
pass has been completed -- see line 1227.

As a result, with the traditional two passes, EQU can't find the label
during the first pass. And since EQU's operand is a critical expression
you get the "symbol `<name>` not defined before use" error.

With additional passes you get the "invalid operand type" warning; it
happens to be the first of the two in parser.c, in line 690.


		
__________________________________ 
Yahoo! FareChase: Search multiple travel sites in one click.
http://farechase.yahoo.com

Re: [Nasm-devel] Re: [Nasm-users] multisection example...

[Jacques M. <jac...@gm...>]

I'd like to retrieve a section size (in fact, multiple sections size)
from another section (which relocated the other sections). Is
section.<secname>.start supposed to be the solution? Should we,
instead, do this:

section mysection
mysectionsize: dd $ - section.mysection.start

And later user [mysectionsize] ? Will I be able to access it from
another section without some weird %define calculations?


On 11/13/05, anonymous coward <nas...@ya...> wrote:
> Frank,
> > > section mysection
> > > mysectionsize equ $ - section.mysection.start
> > >
> > > This will tell me section.mysection.start wasn't defined prior to its=
 use...
> > >
> > > What's wrong?
> >
> > Dunno. I can confirm that it happens. I *think* you're doing everything
> > right. If I add the "-O" switch, the error message changes to "invalid
> > operand type". I suspect a bug. I'll pass this on to the developer's
> > list, and see if anyone has any ideas...
>
> The section.<name>.start label is defined by bin_define_section_labels()
> in outbin.c. However, that function isn't called until after the second
> pass has been completed -- see line 1227.
>
> As a result, with the traditional two passes, EQU can't find the label
> during the first pass. And since EQU's operand is a critical expression
> you get the "symbol `<name>` not defined before use" error.
>
> With additional passes you get the "invalid operand type" warning; it
> happens to be the first of the two in parser.c, in line 690.
>
>
>
> __________________________________
> Yahoo! FareChase: Search multiple travel sites in one click.
> http://farechase.yahoo.com
>
>
> -------------------------------------------------------
> SF.Net email is sponsored by:
> Tame your development challenges with Apache's Geronimo App Server. Downl=
oad
> it for free - -and be entered to win a 42" plasma tv or your very own
> Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
> _______________________________________________
> Nasm-users mailing list
> Nas...@li...
> https://lists.sourceforge.net/lists/listinfo/nasm-users
>


--
Jacques Mony
Programmeur-Analyste
Les services conseils Syst=E9matix inc.

Re: [Nasm-devel] Re: [Nasm-users] multisection example...

[H. P. A. <hp...@zy...>]

Frank Kotler wrote:
> Jacques Mony wrote:
> 
>> Hi,
>>
>>  Can anyone give me an example of how to use section.<secname>.start?
>>
>>  I tried this:
>>
>> ------ test.asm -------
>>
>> section mysection
>>
>> mysectionsize equ $ - section.mysection.start
>> --------------------------
>>
>> This will tell me section.mysection.start wasn't defined prior to its 
>> use...
>>
>> What's wrong?
> 
> 
> Dunno. I can confirm that it happens. I *think* you're doing everything 
> right. If I add the "-O" switch, the error message changes to "invalid 
> operand type". I suspect a bug. I'll pass this on to the developer's 
> list, and see if anyone has any ideas...
> 
> Thanks for testing the multisection support and letting us know!
> 

Okay, sorry for chiming in way, way late...

The reason it doesn't work is because section.mysection.start isn't seen 
by the assembler and linker as being in the same section as $.  Remember 
that outbin is really a linker.  In the case above, it's equivalent to 
$-$$, but the assembler doesn't know that, and if it had been a 
*different* section, it wouldn't have been able to resolve it.

	-hpa