32-bit assembler::how to initialize segment registers

32-bit assembler::how to initialize segment registers

[san]

---------------------------- Original Message ----------------------------
Subject: 32-bit assembler::how to initialize segment registers
From:    "shivam sharma" <shiurya@yahoo.co.in>
Date:    Tue, October 19, 2004 12:07 am
To:      San@cusat.ac.in
--------------------------------------------------------------------------
Hi

am making 32-bit
assembler as project in c under linux platform.
             my problem is how my assembler should
initialize the segment registers.suppose,if user
program format is..........

      .stack[64h]

      .data
     .........
     .........
     .........
      .code
     .........
      .........
     ..........
                   then,on seeing the stack or data or
code how the assembler program should initialize the
segment registers.

thanks in advance

Re: 32-bit assembler::how to initialize segment registers

[zebarbuc]

I don't understand your question...
You want to create your own assembler (like 'as86' prog), but you don't know how
to make it? That's it?
If yes, you'd better buy a related book, i'm afraid that we cannot answer all
your futur requests.
If not, please, explain a little bit your problem...

Fred


Selon san@cusat.ac.in:

> ---------------------------- Original Message ----------------------------
> Subject: 32-bit assembler::how to initialize segment registers
> From:    "shivam sharma" <shiurya@yahoo.co.in>
> Date:    Tue, October 19, 2004 12:07 am
> To:      San@cusat.ac.in
> --------------------------------------------------------------------------
> Hi
>
> am making 32-bit
> assembler as project in c under linux platform.
>              my problem is how my assembler should
> initialize the segment registers.suppose,if user
> program format is..........
>
>       .stack[64h]
>
>       .data
>      .........
>      .........
>      .........
>       .code
>      .........
>       .........
>      ..........
>                    then,on seeing the stack or data or
> code how the assembler program should initialize the
> segment registers.
>
> thanks in advance
> -
> To unsubscribe from this list: send the line "unsubscribe linux-assembly" in
> the body of a message to majordomo@vger.kernel.org
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Re: 32-bit assembler::how to initialize segment registers

[Muthu]

Hi !
I guess you have to refer to intel architecture
manual.
Generally you arent supposed to load the segment
registers directly. That is taken care of by the
loader program. eg: ld.so in GNU/Linux.
This [loading segment registers] is a problem only
if you are making straight binary code, that runs
[eg: Bootloader, Embedded code]. 
For this case do something like
  /* in INTEL syntax */
  mov ax,0xfff
  mov ds,ax
  mov fs,ax
  
Cheers
Muthu


		
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Re: 32-bit assembler::how to initialize segment registers

[Brian Raiter]

> am making 32-bit
> assembler as project in c under linux platform.
>              my problem is how my assembler should
> initialize the segment registers.

Assuming the output of your assembler is a Linux object file, then the
segment registers are not your responsibility. Linux sets up the
segment registers before the user's code is called. If the programmer
wants to do something bizarre and/or clever with segments, then it's
their responsiblity.

b

HLA v1.71 is now available

[Randall Hyde]

Hi all,

HLA v1.71 is now available on Webster at the HLA download page:
http://webster.cs.ucr.edu/AsmTools/HLA/dnld.html

This is a maintenance release, containing the following minor
changes:

 * Corrected a syntax error in the arrays.hhf header file
   (extra parentheses occuring in the test for floating-point
    types)

 * Fixed a problem with the indexing into REAL80 arrays in
   the arrays.hla module in the standard library.

 * Fixed a problem with the mem.isInHeap function.

 * Changed FASM output to use conditional assembly to
   "protect" extrn symbols in case the symbols weren't
   accessed in the file.

I also modified the HLA.DLL code in the "examples"
download to compile correctly when using FHLA.

----------------------------------------------------

HLA, the High-Level Assembler, is a powerful macro
assembly language development system that runs under
Windows and Linux operating systems. Carefully-written
applications are portable between both operating systems
with nothing more than a recompile of the source file.

From a features point of view, HLA is one of the most
powerful assemblers ever written. It's macro and
"compile-time language" facilities far exceed those found
in other assemblers.

HLA was specifically designed to make learning and writing
assembly language as easy as possible. HLA is fully supported
by tons of documentation, example code, and other things
that beginning and advanced programmers will find useful.
The 32-bit edition of "The Art of Assembly Language"
(No Starch Press) teaches introductory assembly language
programming using HLA and is one of the most often-cited
textbooks on the subject.  You can read "The Art of Assembly"
on-line at http://webster.cs.ucr.edu/AoA/index.html.

The HLA system also includes the HLA Standard Library,
a collection of hundreds of ready to use library routines that
simplify assembly language programming and provide (among
other things) a usable interface to the underlying operating system.
Full source code to the Standard Library is available.

The HLA compiler and standard library are public domain and
can be used anyway you see fit.

Cheers,
Randy Hyde

Re: HLA v1.71 is now available

[Claudio Fontana]

Hello,
I've found AoA for Linux html online version at

http://webster.cs.ucr.edu/AoA/Linux/HTML/AoATOC.html

to have problems with the numbering of the chapters.
After 4.7 comes 1.1 and the like.

Claudio


		
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Re: 32-bit assembler::how to initialize segment registers

[Daniel R. Blair]

On Tue, 19 Oct 2004 zebarbuc@free.fr wrote:

> I don't understand your question...
> You want to create your own assembler (like 'as86' prog), but you don't know how
> to make it? That's it?
> If yes, you'd better buy a related book, i'm afraid that we cannot answer all
> your futur requests.
> If not, please, explain a little bit your problem...

Selon,
 	Amen.. if you are not sure about something as elementary as that 
(which isn't elementary, but it is in the context (relatively)), then you 
really need to learn more about the x86 architecture, ELF binary format, 
etc.  There as stated above, this list is to help with specific things, 
assembler related, not to help people write assemblers =]  If you are 
using an assembler, and say, have a piece of code that *SHOULD* work, but 
doesn't, then post it and other eyes may see something/know something that 
you don't and can tell you "Oh, under protected mode that cannot be 
successfully completed, you must go through another register and access 
it indirectly" or something like that..

 	I suggest getting the source to HLA, or NASM, etc. and checking it 
out.  I know it's a lot to go through (both lines of code wise, as well as 
sheer technical data/routines), but, if you plan on writing your own 
assembler, optimized or not.. I am talking about just getting one to work 
and build an executable/binary that will run, based on either a sub-set of 
the x86 instruction set, or the entire x86 instruction set (preferably the 
later), then you need to know the "basics" about how an assembler works, 
how a linker works, parsers, lexical analyzers, etc.  This you need books, 
time, and knowledge, reference tables, etc.  Even to do a straight 
assembly language to machine code translation program.. and that isn't 
doing much.. but it still involves reading ahead, recognizing grammar(s), 
etc. and then acting on them (i.e. loop constructs, etc.)

 	All of this should be something that you already know... if you 
are attempting to write a working assembler in C.  If not, just stop 
writing your assembler now and either start reading, or write something 
else.  Again, NASM is a great, Open Source, x86 assembler that compiles 
under Unix (I run FreeBSD and use NASM, but I know it works on Linux too), 
and I think it even has a version and compiles under Windows as well..

 	HLA (High Level Assembler), which can be found by searching google 
for "HLA High Level Assembly Webster" (the site is called "Webster", not 
sure, but, it's something like www.webster.edu or webster.something.edu, 
etc.  it's not, to my knowledge, webster.com|net|org, so, you need to 
search for it, but, it will be the first thing that comes up I am sure), 
it not only has the HLA (High Level Assembly) language compiler, but, it 
is written by the author of the book, which I own, now that you can 
purchase it in print, rather than just read it online (although the Online 
version gets updated more frequently than the printed version, for obvious 
reasons) entitled "The Art of Assembly Language".  This book is a great 
reference for anyone learning assembly language, but also a great book to 
teach you how things operate, etc.  HLA is more of a cross between a 
high[er] level language and assembler, with things like mutable variables, 
procedures/functions/etc.
 	Check it out and recommend it to people who want to learn more 
about how the actual architecture works.. what are it's quirks, etc.  and 
then also, to ease people into assembly language programming from standard 
procedural languages as well.  Once you have learned how to program in 
HLA, you can take of the "training wheels" and write in pure assembler, 
which HLA can compile.. so.. you can start mixing your old code that used 
HLA constructs that aren't quite valid asm, or, shall I say, not "straight 
assembly language", but, damn close, and a lot more close than C/C++, 
etc., and then finally, you can be programming in pure assembly language 
code by itself, again, using HLA, and you are now capable of programming 
in ASM.

 	Now, even writing code using the HLA libraries and syntax, it is 
compiled, or shall I say, pre-processed, to be pure assembly language, 
before it's compiled, so, it's pretty close, and right on the money (in 
some cases), to what you would code (or would like to have written) by 
hand in a lot of places.  Some places are a *LITTLE* less effecient simply 
because you cannot interpret something dynamically (i.e. the syntax of a 
high level language), and turn it into optimized assembler code in the 
absolute best way, using the least amount of instructions, or cpu cycles 
(as lower instruction count doesn't nessecarily equal lower cpu cycle 
count.)  The HLA libraries are written in pure assembler I think, which is 
why it's so close to hand written assembler once it's been pre-processed, 
but, you get the idea.

 	You can download and/or read the book, The Art of Assembly (AoA) 
online, and it will show you from start to fnish how to write assembl 
langage code, using HLA, and also the differences in HLA and normal x86 
ASM.  It will show you everything you need to know.. and, as I stated, you 
can purchase this book by itself too (which comes with a CD-ROM and other 
things in the book.. like the sample code, sample apps, the book in PDF 
and HTML format, the RadHLA IDE for HLA, etc.)  But, if you buy the book, 
you will want to snag the newest version of the HLA distribution, and then 
you can follow along with the book.. just read the CHANGELOG to see if 
anything major has changed between versions (incompatibilities, etc.)

Hope this gets you started bro.. I applaud the effort in wanting to write 
an assembler, as it's a monumental task.. whether for a project or for a 
tool to be used by others, in place of the existing tools which are 
already mature, used by many, and supported on lots of architectures.  So, 
if you aren't doing this "just to do it", and you want people to start 
using it, etc.  You are going to need a lot of knowledge on your side to 
make yours better than what's already out there bro =]  If you are doing 
it as a C.S. project, than, go for it, and good luck.  If you honestly 
have the skills and the knowledge that it takes to write an assembler, and 
you have the time (which obviously you do, or at least think you do, or 
you wouldn't be attempting to write one), you might consider joining the 
NASM Open Source development team, or some other Open Source assembler 
team, and that way you can help aid in making an existing product perform 
better, rather than re-inventing the wheel and most likely (no offense to 
you meant at all) doing it worse than it already exists.. simply because 
the other projects have had time for user feedback, etc. and have improved 
because of knowledge gained during development, testing, and in other 
areas.. starting from scratch will give you a good feeling when you can 
compile your own "Hello, World!" program/binary and actually run it and 
have it work, but, adding to a project like NASM will benefit the 
community a lot more..

 	Hope some/any of this helped you, if not, at least I got it out in 
the open and perhaps it will be archived somewhere and come up on a search 
of older news group postings for some other pour soul seeking knowledge =]

Cheers,

Danny
                            = Daniel Blair =
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- dblair@realcoders.org -                   [http://www.realcoders.org]
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Re: 32-bit assembler::how to initialize segment registers

[Fred Marmond]

Hey, guys, I WAS NOT THE MAN WHO ASKED THE ORIGINAL QUESTION!

I was only answering to "san@cusat.ac.in", telling him that I just didn't 
understand what he wanted to know!
Look at this list archive, I don't feel I am a newbie in x86 assembly.
What I said, in other words:
"if you don't know anything about assembly in general, and basics of binary 
formats as ELF, you'd better starting with buying a assembly-related book, we 
(guys in the list) won't have time to make you a full course on this 
subject."


Or perhapse my english is soo bad too, that I was not able to make you 
understand my reply...


Fred

Le mercredi 20 Octobre 2004 03:57, Daniel R. Blair a écrit :
> On Tue, 19 Oct 2004 zebarbuc@free.fr wrote:
> > I don't understand your question...
> > You want to create your own assembler (like 'as86' prog), but you don't
> > know how to make it? That's it?
> > If yes, you'd better buy a related book, i'm afraid that we cannot answer
> > all your futur requests.
> > If not, please, explain a little bit your problem...
>
> Selon,
>  	Amen.. if you are not sure about something as elementary as that
> (which isn't elementary, but it is in the context (relatively)), then you
> really need to learn more about the x86 architecture, ELF binary format,
> etc.  There as stated above, this list is to help with specific things,
> assembler related, not to help people write assemblers =]  If you are
> using an assembler, and say, have a piece of code that *SHOULD* work, but
> doesn't, then post it and other eyes may see something/know something that
> you don't and can tell you "Oh, under protected mode that cannot be
> successfully completed, you must go through another register and access
> it indirectly" or something like that..
>
>  	I suggest getting the source to HLA, or NASM, etc. and checking it
> out.  I know it's a lot to go through (both lines of code wise, as well as
> sheer technical data/routines), but, if you plan on writing your own
> assembler, optimized or not.. I am talking about just getting one to work
> and build an executable/binary that will run, based on either a sub-set of
> the x86 instruction set, or the entire x86 instruction set (preferably the
> later), then you need to know the "basics" about how an assembler works,
> how a linker works, parsers, lexical analyzers, etc.  This you need books,
> time, and knowledge, reference tables, etc.  Even to do a straight
> assembly language to machine code translation program.. and that isn't
> doing much.. but it still involves reading ahead, recognizing grammar(s),
> etc. and then acting on them (i.e. loop constructs, etc.)
>
>  	All of this should be something that you already know... if you
> are attempting to write a working assembler in C.  If not, just stop
> writing your assembler now and either start reading, or write something
> else.  Again, NASM is a great, Open Source, x86 assembler that compiles
> under Unix (I run FreeBSD and use NASM, but I know it works on Linux too),
> and I think it even has a version and compiles under Windows as well..
>
>  	HLA (High Level Assembler), which can be found by searching google
> for "HLA High Level Assembly Webster" (the site is called "Webster", not
> sure, but, it's something like www.webster.edu or webster.something.edu,
> etc.  it's not, to my knowledge, webster.com|net|org, so, you need to
> search for it, but, it will be the first thing that comes up I am sure),
> it not only has the HLA (High Level Assembly) language compiler, but, it
> is written by the author of the book, which I own, now that you can
> purchase it in print, rather than just read it online (although the Online
> version gets updated more frequently than the printed version, for obvious
> reasons) entitled "The Art of Assembly Language".  This book is a great
> reference for anyone learning assembly language, but also a great book to
> teach you how things operate, etc.  HLA is more of a cross between a
> high[er] level language and assembler, with things like mutable variables,
> procedures/functions/etc.
>  	Check it out and recommend it to people who want to learn more
> about how the actual architecture works.. what are it's quirks, etc.  and
> then also, to ease people into assembly language programming from standard
> procedural languages as well.  Once you have learned how to program in
> HLA, you can take of the "training wheels" and write in pure assembler,
> which HLA can compile.. so.. you can start mixing your old code that used
> HLA constructs that aren't quite valid asm, or, shall I say, not "straight
> assembly language", but, damn close, and a lot more close than C/C++,
> etc., and then finally, you can be programming in pure assembly language
> code by itself, again, using HLA, and you are now capable of programming
> in ASM.
>
>  	Now, even writing code using the HLA libraries and syntax, it is
> compiled, or shall I say, pre-processed, to be pure assembly language,
> before it's compiled, so, it's pretty close, and right on the money (in
> some cases), to what you would code (or would like to have written) by
> hand in a lot of places.  Some places are a *LITTLE* less effecient simply
> because you cannot interpret something dynamically (i.e. the syntax of a
> high level language), and turn it into optimized assembler code in the
> absolute best way, using the least amount of instructions, or cpu cycles
> (as lower instruction count doesn't nessecarily equal lower cpu cycle
> count.)  The HLA libraries are written in pure assembler I think, which is
> why it's so close to hand written assembler once it's been pre-processed,
> but, you get the idea.
>
>  	You can download and/or read the book, The Art of Assembly (AoA)
> online, and it will show you from start to fnish how to write assembl
> langage code, using HLA, and also the differences in HLA and normal x86
> ASM.  It will show you everything you need to know.. and, as I stated, you
> can purchase this book by itself too (which comes with a CD-ROM and other
> things in the book.. like the sample code, sample apps, the book in PDF
> and HTML format, the RadHLA IDE for HLA, etc.)  But, if you buy the book,
> you will want to snag the newest version of the HLA distribution, and then
> you can follow along with the book.. just read the CHANGELOG to see if
> anything major has changed between versions (incompatibilities, etc.)
>
> Hope this gets you started bro.. I applaud the effort in wanting to write
> an assembler, as it's a monumental task.. whether for a project or for a
> tool to be used by others, in place of the existing tools which are
> already mature, used by many, and supported on lots of architectures.  So,
> if you aren't doing this "just to do it", and you want people to start
> using it, etc.  You are going to need a lot of knowledge on your side to
> make yours better than what's already out there bro =]  If you are doing
> it as a C.S. project, than, go for it, and good luck.  If you honestly
> have the skills and the knowledge that it takes to write an assembler, and
> you have the time (which obviously you do, or at least think you do, or
> you wouldn't be attempting to write one), you might consider joining the
> NASM Open Source development team, or some other Open Source assembler
> team, and that way you can help aid in making an existing product perform
> better, rather than re-inventing the wheel and most likely (no offense to
> you meant at all) doing it worse than it already exists.. simply because
> the other projects have had time for user feedback, etc. and have improved
> because of knowledge gained during development, testing, and in other
> areas.. starting from scratch will give you a good feeling when you can
> compile your own "Hello, World!" program/binary and actually run it and
> have it work, but, adding to a project like NASM will benefit the
> community a lot more..
>
>  	Hope some/any of this helped you, if not, at least I got it out in
> the open and perhaps it will be archived somewhere and come up on a search
> of older news group postings for some other pour soul seeking knowledge =]
>
> Cheers,
>
> Danny
>                             = Daniel Blair =
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> - dblair@realcoders.org -                   [http://www.realcoders.org]
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
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