Screen control functions

[OziRus]

Hi,

This is my first message on this group. I want to ask something about
screen-drawing functions. I wrote and compiled below code succesfully
on TC IDE in Win-xp. Then i tried to work it on dos but it didn't work.
It runs but doesn't draw anything on screen. Could you say my fault? I
know far,dev and near are a bit problematic in xp but i think compiling
with Tc and running in dos might run it? [I didn't try it on linux yet]

Thanks for everything...

#include <stdio.h>
#include <conio.h>

char far *vp=(char far *)0xB0000000;
void _write(int row,int col,int ch)
{
char far *scrp=vp;
scrp+=row*160+c ol*2;
*scrp=ch;
}

int main()
{
_write(10,10,'t ');
_write(10,11,'e ');
_write(10,12,'s ');
_write(10,13,'t ');
return 0;
}

[OziRus]

not "dev". It was huge :)

[jacob navia]

OziRus wrote:

Hi,

This is my first message on this group. I want to ask something about
screen-drawing functions. I wrote and compiled below code succesfully
on TC IDE in Win-xp. Then i tried to work it on dos but it didn't work.
It runs but doesn't draw anything on screen. Could you say my fault? I
know far,dev and near are a bit problematic in xp but i think compiling
with Tc and running in dos might run it? [I didn't try it on linux yet]

Thanks for everything...

#include <stdio.h>
#include <conio.h>

char far *vp=(char far *)0xB0000000;
void _write(int row,int col,int ch)
{
char far *scrp=vp;
scrp+=row*160+c ol*2;
*scrp=ch;
}

int main()
{
_write(10,10,'t ');
_write(10,11,'e ');
_write(10,12,'s ');
_write(10,13,'t ');
return 0;
}

You have to run under MSDOS, not windows XP.

Contrary to what *many* people think, MSDOS is dead since more than 10
years, I do not remember exactly when was it, maybe 1995.

Contrary to what many people think, the "DOS WINDOW" is just
an EMULATION of text mode msdos, with the same commands,
etc.

The MSDOS emulation will NOT emulate the writing to screen memory,
as it seems.

Maybe a better idea would be to use the console mode with a 32 bit
compiler, and obtain the same result.

So, you have two solutions:

1) Get a better compiler
2) Get MSDOS and run under msdos by booting from a disquette.
You will get many advantages:
Only 640K of memory. No more problems with that huge amount
of RAM that you do not know what to do about
TC IDE will run better and all dos programs will work.

The choice is yours

jacob

[OziRus]

Thanks for your reply;

jacob navia wrote:

Get a better compiler

Dev C++ couldn't compile the same code that I used with TC. The errors
were like this;

C:\Tc\BIN\KARAK TER.CPP:4: error: expected init-declarator before '*'
token
C:\Tc\BIN\KARAK TER.CPP:4: error: expected `,' or `;' before '*' token
C:\Tc\BIN\KARAK TER.CPP: In function `void _writec(int, int, int)':
C:\Tc\BIN\KARAK TER.CPP:9: error: expected primary-expression before
"char"
C:\Tc\BIN\KARAK TER.CPP:9: error: expected `;' before "char"

C:\Tc\BIN\KARAK TER.CPP:10: error: `scrp' undeclared (first use this
function)
C:\Tc\BIN\KARAK TER.CPP:10: error: (Each undeclared identifier is
reported only once for each function it appears in.)

I couldn't understand why TC compiled and why dev c++ not...

So, I think I should try more interesting methods for drawing. :p

[jacob navia]

OziRus wrote:

Thanks for your reply;

jacob navia wrote:

>Get a better compiler

Dev C++ couldn't compile the same code that I used with TC. The errors
were like this;

C:\Tc\BIN\KARAK TER.CPP:4: error: expected init-declarator before '*'
token
C:\Tc\BIN\KARAK TER.CPP:4: error: expected `,' or `;' before '*' token
C:\Tc\BIN\KARAK TER.CPP: In function `void _writec(int, int, int)':
C:\Tc\BIN\KARAK TER.CPP:9: error: expected primary-expression before
"char"
C:\Tc\BIN\KARAK TER.CPP:9: error: expected `;' before "char"

C:\Tc\BIN\KARAK TER.CPP:10: error: `scrp' undeclared (first use this
function)
C:\Tc\BIN\KARAK TER.CPP:10: error: (Each undeclared identifier is
reported only once for each function it appears in.)

I couldn't understand why TC compiled and why dev c++ not...

So, I think I should try more interesting methods for drawing. :p

I repeat:

You can't move characters and show characters in the screen by
assigning the characters to some pointer as you do now.

In MSDOS, the machine looked at that address to show the 80x24
video display (if I remember correctly).

This is NO LONGER THE CASE unless you still run MSDOS.

Then, you can't compile and RUN that.

If you want to stay under windows xp there is a compatibility
library for turbo c console I/O with lcc-win32 called
tcconio.lib

You have there functions like "highvideo" "clrscr" and similar
functions, all of them with the same interface that turbo C
used for text mode.

You can download the lcc-win32 compiler from
http://www.cs.virginia.edu/~lcc-win32

Note that lcc-win32 will NOT compile the above code
either. You will have to change your functions to:
gotoxy() and puttextA() or similar functions

jacob

[Coos Haak]

Op Sun, 03 Sep 2006 20:06:15 +0200 schreef jacob navia:

The MSDOS emulation will NOT emulate the writing to screen memory,
as it seems.

But surprisingly it DOES, even under XP. If that gives consoloation ;-)
--
Coos

[Coos Haak]

Op Sun, 03 Sep 2006 20:38:15 +0200 schreef jacob navia:

In MSDOS, the machine looked at that address to show the 80x24
video display (if I remember correctly).

This is NO LONGER THE CASE unless you still run MSDOS.

Then, you can't compile and RUN that.

<OT>
I've used TC 2.01 some time ago and it works with W98 and XP. Don't tell us
nonsense.
</OT>
--
Coos

[J. J. Farrell]

OziRus wrote:

>
This is my first message on this group. I want to ask something about
screen-drawing functions. I wrote and compiled below code succesfully
on TC IDE in Win-xp. Then i tried to work it on dos but it didn't work.
It runs but doesn't draw anything on screen. Could you say my fault? I
know far,dev and near are a bit problematic in xp but i think compiling
with Tc and running in dos might run it? [I didn't try it on linux yet]

Thanks for everything...

#include <stdio.h>
#include <conio.h>

char far *vp=(char far *)0xB0000000;
void _write(int row,int col,int ch)
{
char far *scrp=vp;
scrp+=row*160+c ol*2;
*scrp=ch;
}

int main()
{
_write(10,10,'t ');
_write(10,11,'e ');
_write(10,12,'s ');
_write(10,13,'t ');
return 0;
}

You'd be far better off asking in a group which discusses programming
on MS Windows. comp.lang.c concentrates on the C language itself, and
its aspects and uses which are independent of the system it's running
on. Your program is very dependent on the environment you're using -
for example <conio,his not part of C as such. C itself doesn't have
any concept of a screen, and mechanisms you use to control a screen (on
systems which have one) are different on different Operating Systems.

You'll find far more people who are expert on writing programs specific
to MS operating systems in the newsgroups which are dedicated to the
subject.

[Flash Gordon]

jacob navia wrote:

<snip>

Contrary to what *many* people think, MSDOS is dead since more than 10
years, I do not remember exactly when was it, maybe 1995.

Incorrect. Windows95, Windows98 and even WindowsME actually had DOS 7.x
underneath and in all of them (although with ME it was difficult) you
could get them to boot to a DOS prompt without loading Windows at all.

In addition, you still get some stuff distributed as bootable DOS disk
images. Such as BIOS upgrades. Since this has been the case on some new
machines even after the year 2000 there are obviously still some
programs being run under DOS.

Contrary to what many people think, the "DOS WINDOW" is just
an EMULATION of text mode msdos, with the same commands,
etc.

True.

The MSDOS emulation will NOT emulate the writing to screen memory,
as it seems.

<snip>

Definitely not entirely true. I've run old DOS based games that did
graphics and sound using their own built in drivers under XP. It might
not really access the screen, but XP traps the attempt (when used in the
correct way) and renders the expected result inside the applications window.

For further discussion on this please go to a Windows group where they
will know all about the compatibility modes of XP.
--
Flash Gordon
--
Flash Gordon

[jacob navia]

Coos Haak wrote:

Op Sun, 03 Sep 2006 20:38:15 +0200 schreef jacob navia:

>>In MSDOS, the machine looked at that address to show the 80x24
video display (if I remember correctly).

This is NO LONGER THE CASE unless you still run MSDOS.

Then, you can't compile and RUN that.

<OT>
I've used TC 2.01 some time ago and it works with W98 and XP. Don't tell us
nonsense.
</OT>

You mean you write into 0xB0000000 and you see the characters
in the screen ???

That would be highly surprising, specially under windows xp