Bran's kernel keyboard

[xyjamepa]

hi guys...
I,ve been trying to write a "getch()" to Bran's kernel tutorial but
when i print out this char using the "putch(char c)"
it is printed on the whole screen with out stop could you tell me how can i write this function?

[GLneo]

well the way i did it, you have an array

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#define STDINSZ 1024
unsigned char currentStdin[STDINSZ];

with is your key buffer, now every time you get a key (

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void keyboard_handler(struct regs *r)

) put the ascii key in the table, but you need to know were in the table, so make a variable (top) and do this

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currentStdin[top] = key;

and remeber to move up top every key so you dont write over other keys in the table

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top++;

, now if the table fills up

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if(top > STDINSZ)

reset top to zero. now you may be thinking what happens when top starts over it will overwrite keys, so make a new variable (bottom) to keep track of the start of the key string and

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if((Top + 1) == Bottom)

dont do anything. now to get the keys out just read from

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currentTop[bottom]

put it all together you get:

[GLneo]

[attach]

[xyjamepa]

my code:
unsigned char getch()
{
unsigned char scancode='\0';
while(scancode=='\0')
{
scancode = inportb(0x60);
}
return kbdus[scancode];

}
and now :
unsigned char c=getch();
putch(c);
where is my wrong

[xyjamepa]

okay guys...
let us keep it simple...
i need your feedback...
where are you?

[Pype.Clicker]

okay guys...
let us keep it simple...
i need your feedback...
where are you?

out for lunch ... sleeping ... at work ... who knows.

btw, i'm not much surprised to see your character being painted all over the screen. I/O port 0x60 is a "whiteboard" between you and the keyboard controller. When you read it, you do not remove what was there previously, so if you poll it continuously, you'll get the same value continuously. And no, reading it doesn't turn it back to 0.

Moreover, you should make the distinction between "keypress" and "keybreak" codes you find there.

What you need to do here is to use an interrupt handler. Whenever something new has been placed on the "whiteboard", the keyboard controller rises an interrupt. Just watch that and only read the I/O port after you received an interrupt.

That and more in the FAQ.

[Candy]

okay guys...
let us keep it simple...
i need your feedback...
where are you?

If you need timely response of a specified level and with a minimum of help, you should consider hiring somebody to help you. It's expensive.

We're in no way obliged to even read what you type, let alone answer your question. Realise that everybody here is doing this in their free time. You don't tell anybody what to do with their free time.

[xyjamepa]

thanx for your reply!!!
but... you did not help me
give me some code...

[Kemp]

If you are going to succeed at OS dev you need to be competent enough to be able take the pointers and advice given here and work with them, code isn't going to be delivered to you pre-written.

[xyjamepa]

ok
would somebody please correct my code...

[xyjamepa]

hello
I worte the "getch()" function and my problem is:
when i call this function for the first time it works normally,but
when i call it agin it prints the previous char without any
input from me so...
first time i call getch(),i press some key it prints the asciikey
second time call getch(),prints the previous asciikey without
any input from me!!!
you get it?

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void getch()
{
 unsigned char c='\0';
 while(c=='\0'){
 c=inportb(0x60);
 }
 switch(c)
  {
   case 0x1e:{putch('a');break;}    
   case 0x30:{putch('b');break;}
   .
   .
   .
   .
   case 0x2c:{putch('z');break;}
  }
}

please note:
I installed the keyboard handler into IRQ1
thanx

[Candy]

Did you clear the keyboard buffer?

[earlz]

omg

give me some code...

lol closely resembles "gimme teh codez!!11" lol

but on topic

iirc the keyboard keeps the keypressed in the port so that you can read it more than once hence why you have to use interrupts so try using ints

[xyjamepa]

No i didn't clear the keyboard buffer.
how can i do that?

[Candy]

No i didn't clear the keyboard buffer.
how can i do that?

instead of peeking at the keyboard buffer, read the keyboard buffer.

Short answer: RTFM.