From:	"John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Could someone help me with Nasm module linking?
Date:	Mon, 17 Nov 1997 20:56:01 +0000
Organization:	Two pounds of chaos and a pinch of salt
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Reply-To:	fighteer AT cs DOT com
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To:	djgpp AT delorie DOT com
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Risto J. Sutinen wrote:
> 
> I have tryed to compile and link following source files using Nasm and DJGPP. So far I have got only error messages. What the heck is wrong?? Someone help me out please!

Where shall I start?  Your code is a horrid mixture of 16-bit techniques
that don't work in 32-bit protected mode, invalid assumptions about the
way DJGPP works, and all around bad programming techniques.  Let me
point out the major problems...

> _Fillscrn:
>         push    ebp
>         mov     ebp, esp
> 
>         mov     ax, 0A000h
>         mov     es, ax
>         xor     di, di

Here it appears that you are trying to write directly to video memory. 
This is a major no-no under protected mode and will NOT work the way you
expect.  In fact, it will crash your computer.  Please read chapters 10
and 17 of the DJGPP FAQ (v2/faq210b.zip from SimTel or online at
http://www.delorie.com/djgpp/v2faq/) to learn how to do this in
protected mode.

> #include <go32.h>
> #include <sys/farptr.h>

I assume you use far pointers at some point in your code, or these
includes are useless.  Besides, far and near pointers in DJGPP are
totally unrelated to 16-bit far and near pointers.  Read the FAQ.

> #include <conio.h>
> #include <stdio.h>
> 
> #define VGA256 0x13
> #define TEXT_MODE 0x03
> 
> extern void Fillscrn(int color);
> 
> void main(void)

The ANSI standard states that main() must return an integer.  Please
take your programming book back to where you bought it and demand a
refund, if this is what it's teaching you.  If you learned this from a
friend, shoot him.  I cannot stand people who _teach_ incorrect
programming.

> {
>         int t;
> 
>         // Aseta n?ytt"tila 320*200*256
>         textmode(VGA256);

Please read the documentation for the textmode() function.  Its very
name should clue you in; it's meant for setting TEXT modes, not graphics
modes.  Here's an example of a function to change the graphics mode:

void setmode( int mode )
{
    __dpmi_regs r;

    r.h.al = 0;
    r.h.ah = mode;
    __dpmi_int( 0x10, &r );

    return;
}

>         // T?yt? n?ytt" 1:ll?
>         for (t=0; t<1000; t++)
>         void Fillscrn(t);

Are you declaring this function, or calling it?  This won't even
compile, much less run.  Try just plain,
    Fillscrn(t);

>         // Odota n?p?imen painallusta
>         while(!kbhit()) {}
> 
>         // Palaa tekstitilaan
>         textmode(TEXT_MODE);

This is not the correct way to restore the text mode, either.  Please
read the documentation.

> }

Oh, and you need a return 0; here at the end to satisfy the compiler.

This is C, not BASIC.  Precision is a must.  :)  (sorry, BASIC gurus)

hth

-- 
---------------------------------------------------------------------
|      John M. Aldrich       | "Autocracy is based on the assumption|
|       aka Fighteer I       | that one man is wiser than a million |
|   mailto:fighteer AT cs DOT com   | men.  Let's play that over again,    |
| http://www.cs.com/fighteer | too.  Who decides?"   - Lazarus Long |
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