OSDev.org

Hi again everyone. Eclipse OS is on its way and can now accept input from the keyboard. And I wanted the user to be able to type "clear" to make the screen clear and then start another function like shell() again after it. So here's my problem: The clear function clears the screen, but it doesn't move the cursor back to (x,y) 0, 0. It just prints the next function a y value below the one you were at before you ran the clear function. my clear function is as follows:

void Video::clear()      
{
unsigned int i;
for(i = 0; i < (scrWidth * scrHeight); i++)
{
videomem = (unsigned char) ' ' | (colour << ;
}
setcursor(0,0); //sets the xy values, but it isnt working.
}

Please help!

Why isn't it working ?
Make sure that:
- setcursor() works properly, when otherwise called
- make sure the 2 bytes are (the bytes that you use to "erase" the screen) 0x0700 is, else you won't see the cursor

HTH, Dennis

There was a good OS made in about 97 called "Eclipse OS"
are you the same one ?
And as i do not use C, I can not help you on your clear screen problem.

ASHLEY4.

Ashley: are you referring to EOS, the game&demo 32 bits dosextender ?

@Clicker,That's the one, Nice bit of programming that was .

ASHLEY4.

Nope
I didn't know that there was an OS called Eclipse OS. This is one that I've started recently. Still can't figure the clear() out. It's almost as if when I clear the screen the x y position doesn't get saved before I write some text to the screen at a new line down.
Some help would be appreciated. Thanx. I've also posted my setcursor() function.

void Video::setcursor(unsigned x, unsigned y)   
{
unsigned short offset;
offset = x + y * scrWidth;
outportb(crtc_mem + 0, 14);
outportb(crtc_mem + 1, offset >> ;
outportb(crtc_mem + 0, 15);
outportb(crtc_mem + 1, offset);
}

I think your set cursor function doesn't actually set your physical X, Y cursor position. (The ones you use in your printf and friends functions). Your set cursor function only appears to change the hardware cursor...which will not effect where you write to on the screen next...

Okay
Thats what I thought, but how to I change the physical x and y pos. I call the clear function when the word clear is typed. So how do I keep the x y coordinates from one function (clear) to the next? Here's my video write function.

Thanx

void Video::put(char c)
{
int t;
switch(c)
{
case '\r':
xpos = 0;
break;
case '\n':
xpos = 0;
ypos++;
break;
case 8:
t = xpos + ypos * scrWidth;
if(t > 0)
{
t--;
}
if(xpos > 0)
{
xpos--;
}
else if(ypos > 0)
{
ypos--;
xpos = scrWidth - 1;
}
*(videomem + t) = ' ' | (colour << ;
break;
default:                  
if(c < ' ') break;            
*(videomem + xpos + ypos * scrWidth) = c | (colour << ;
xpos++;                     
if(xpos == scrWidth)         
{
xpos = 0;
ypos++;
}
break;
}
if(ypos == scrHeight)         
{
scrollup();               
ypos--;                  
}
setcursor(xpos, ypos);
}

Well it would appear your using C++, and I'll assume xpos and ypos are members of your Video class.

So you can set xpos and ypos to zero from within your clear function.

Check out http://www.invalidsoftware.net/, lots of C++ Kernel problem solving in the forum, and sections.

okay, I figured it out. Thanx alot for the help. Now what I need to figure out is how to shutdown an ATX computer. I have a reboot function that sends outportb (0x64, 0xfe); to the bios. Could someone tell me what command to send for an ATX shutdown?
I'm using C++ if you were wondering. Thanx

EclipseOS wrote: okay, I figured it out. Thanx alot for the help. Now what I need to figure out is how to shutdown an ATX computer. I have a reboot function that sends outportb (0x64, 0xfe); to the bios. Could someone tell me what command to send for an ATX shutdown?
I'm using C++ if you were wondering. Thanx

The BIOS doesn't listen on ports. Port 0x64 is the keyboard controller, and yes, it has a processor reset function. Try loading some different value in the cmos or use a bios function.

Like...

EclipseOS wrote: Like...

try ralf brown's list?

http://www.ctyme.com/intr/cat-031.htm

entire category on power management. Try the first set (APM).