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;
}

[Flash Gordon]

jacob navia wrote:

Flash Gordon wrote:

>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.

True, but not under windows xp, the system the OP said he
was using.

Therefore what you said was false. DOS has *not* been dead for more than
10 years. If you are talking about XP specifically, that is under 10
years old so you were *still* wrong.

>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.

True. I used one yesterday from MAXTOR. It boots
MSDOS (Digital Research) and tests your MAXTOR hard drive.

If it is the Digital Research version then it is DRDOS *not* MSDOS.
There are other versions of DOS as well. However, this agrees with what
I said that you were *wrong* to claim that DOS is dead.

<snip>

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

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.

Yes, you can change the emulator behavior with the "shortcut properties"
if I remember correctly, and maybe it emulates that hacks too.

So you were wrong here as well. This is why you should direct posters to
the *correct* group. It is pure chance that a couple of us happen to
know a little more about this that you do. Enough to point out that you
were almost completely wrong and definitely completely wrong about the
points that affect the OP.

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

AHHHH

Nostalgia is not what it used to be ...

:-)

So don't post advice about things you have forgotten (if you ever knew
them). Instead redirect people to appropriate groups where they will
find the *real* experts on the topic when it is not topical here.
--
Flash Gordon

[jacob navia]

Flash Gordon wrote:

jacob navia wrote:

>Flash Gordon wrote:

>>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.

True, but not under windows xp, the system the OP said he
was using.

Therefore what you said was false. DOS has *not* been dead for more than
10 years. If you are talking about XP specifically, that is under 10
years old so you were *still* wrong.

MSDOS was dead when windows 95 came out.
Microsoft has discontinued support for it YEARS ago.
Yes, in some embedded systems it goes on, just as the
VAX is somehwere maybe still running, and I do not know if
you know this, but I can run even a PDP11 in emulation
now.

But (I hope) you will agree with me that MSDOS is quite dead since quite
a few years!!!

>>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.

True. I used one yesterday from MAXTOR. It boots
MSDOS (Digital Research) and tests your MAXTOR hard drive.

If it is the Digital Research version then it is DRDOS *not* MSDOS.
There are other versions of DOS as well. However, this agrees with what
I said that you were *wrong* to claim that DOS is dead.

Digital Research still distributes that stuff, and it is still used.
Besides, the PDP 11 emulator is still running, and I can emulate
an Apple ][ in the Mac. Software never dies.

But in *some* sense, the PDP 11 *is dead* !!!

<snip>

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

Yes, you can change the emulator behavior with the "shortcut properties"
if I remember correctly, and maybe it emulates that hacks too.

So you were wrong here as well. This is why you should direct posters to
the *correct* group. It is pure chance that a couple of us happen to
know a little more about this that you do. Enough to point out that you
were almost completely wrong and definitely completely wrong about the
points that affect the OP.

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

AHHHH

Nostalgia is not what it used to be ...

:-)

So don't post advice about things you have forgotten (if you ever knew
them). Instead redirect people to appropriate groups where they will
find the *real* experts on the topic when it is not topical here.

The advice I gave the OP was to get a more up-to-date system and
environment. In my first answer said

Get a better compiler

That stills tands and it is not wrong.

[Keith Thompson]

jacob navia <ja***@jacob.re mcomp.frwrites:
[...]

MSDOS was dead when windows 95 came out.
Microsoft has discontinued support for it YEARS ago.

[...]

Yes, in some embedded systems it goes on, just as the
VAX is somehwere maybe still running, and I do not know if
you know this, but I can run even a PDP11 in emulation
now.

But (I hope) you will agree with me that MSDOS is quite dead since
quite a few years!!!

I will neither agree nor disagree, because I do not care. The
question has nothing to do with the C programming language, and is
therefore off topic in this newsgroup.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[OziRus]

Thanks "Bill". I got it.
jacob navia wrote:

William J. Leary Jr. wrote:

"OziRus" <ca************ @gmail.comwrote in message
news:11******** *************@h 48g2000cwc.goog legroups.com...

This might better be asked in comp.os.msdos.p rogrammer or a windows group.

But...

>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?

It should work under a Command Line session (often called a "DOS session")
under XP.

But...

>char far *vp=(char far *)0xB0000000;

B0000000 is the Monochrome Display Adapter (MDA) base address.

Some color adapters will emulate the MDA, but most won't. Of the those I've
used, only one (see below).

If you're runing this under Windows, it's going to think it's got a color
adapter of some kind*, so you need B8000000.

I've just compiled your program, as a real mode DOS .EXE, and run it under
MS-DOS 5.0, Windows ME and Windows XP. With B0000000 it only works on the
MS-DOS machine. This one explicitly emulates MDA (as per comment above). If I
use B8000000 it works as expected under all three.

- Bill
____________
* Your display adapter probably has to emulate the Color Graphics Adapter (CGA)
for this to work. The majority of adapters do or, at least, did last time I
shopped around (about six months back).

Bill (Your second names isn't Gates I presume ? :-)

You are a TRUE MSDOS HACKER (tm)

This is actually the reason!!!!

Congratulations Bill.

jacob

[Flash Gordon]

Keith Thompson wrote:

jacob navia <ja***@jacob.re mcomp.frwrites:

<snip>

I will neither agree nor disagree, because I do not care. The
question has nothing to do with the C programming language, and is
therefore off topic in this newsgroup.

I do care and I know, but I agree this is the wrong place for it. I've
taken it to email.
--
Flash Gordon

[Kenneth Brody]

jacob navia wrote:

>
OziRus wrote:

[...]

char far *vp=(char far *)0xB0000000;

[...]

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.

And, contrary to that, Windows 95, 98, and Me all run on top of MS-DOS,
despite what Microsoft would have liked you to believe.

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.

Yes it does, _if_ you are running a 16-bit MS-DOS program.

<drift mode="even further OT">

In a console window, type "debug". Then, at the debugger's "-" prompt,
type "f b800:0 l400 41 04". (Note that "l400" is "el four zero zero",
and "41" is "four one".) The first 6-1/2 lines will fill with red "A"s.
(Character 0x41, attribute 0x04.)

Also, note that the address is "b800:0000" , not "b000:0000" as the
code from the OP used. If the compiler is generating 16-bit real-mode
executables, then changing to 0xb8000000 may "fix" the problem.

</drift>

[...]

--
+-------------------------+--------------------+-----------------------+
| Kenneth J. Brody | www.hvcomputer.com | #include |
| kenbrody/at\spamcop.net | www.fptech.com | <std_disclaimer .h|
+-------------------------+--------------------+-----------------------+
Don't e-mail me at: <mailto:Th***** ********@gmail. com>