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unsigned char *videoram = (unsigned char *) 0xb8000;
   videoram[0] = 65; /* character 'A' */
   videoram[1] = 0x07; /* forground, background color. */

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puts(char *s) {
     while(*s) {
          videoram[offset++] = *s; /* character 'A' */
          videoram[offset++] = 0x07; /* forground, background color. */
          s++;
      }
}

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puts(const char * s)

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puts("A string to print");

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int x=0, y=0;
void puts(const char *str) {
     while(*str) {
          if(*str == '\n')
          { //Handle newline
                str++;
                x=0;y++;
          }
          videoram[y*80+x] = *str; /* character */
          videoram[y*80+x+1] = 0x07; /* forground, background color. */
          x++;
          if(x > 80)
          { //If we reached to edge of the screen
                 x=0;
                 y++;
          }
          str++;
     }
}

int main() {
     ...
     puts("Hi\n");
     ...
}

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unsigned char *videoram = (unsigned char *) 0xb8000;
int x=0, y=0;

void puts(const char *str) {
     while(*str) {
          if(*str == '\n')
          { //Handle newline
                str++;
                x=0;y++;
          }
          videoram[y*80+x] = *str; /* character */
          videoram[y*80+x+1] = 0x07; /* forground, background color. */
          x++;
          if(x > 80)
          { //If we reached to edge of the screen
                 x=0;
                 y++;
          }
          str++;
     }
}

void kmain( void* mbd, unsigned int magic )
{
	puts("Hi\n");
}

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// monitor.h -- Defines the interface for monitor.h
// From JamesM's kernel development tutorials.

#ifndef MONITOR_H
#define MONITOR_H

#include "common.h"

int cursor_x, cursor_y = 0;
unsigned char *video_memory = (unsigned char *) 0xb8000;

// Scrolls the text on the screen up by one line.
static void scroll()
{

   // Get a space character with the default colour attributes.
   u8int attributeByte = (0 /*black*/ << 4) | (15 /*white*/ & 0x0F);
   u16int blank = 0x20 /* space */ | (attributeByte << 8);

   // Row 25 is the end, this means we need to scroll up
   if(cursor_y >= 25)
   {
       // Move the current text chunk that makes up the screen
       // back in the buffer by a line
       int i;
       for (i = 0*80; i < 24*80; i++)
       {
           video_memory[i] = video_memory[i+80];
       }

       // The last line should now be blank. Do this by writing
       // 80 spaces to it.
       for (i = 24*80; i < 25*80; i++)
       {
           video_memory[i] = blank;
       }
       // The cursor should now be on the last line.
       cursor_y = 24;
   }

// Updates the hardware cursor.
static void move_cursor()
{
   // The screen is 80 characters wide...
   u16int cursorLocation = cursor_y * 80 + cursor_x;
   outb(0x3D4, 14);                  // Tell the VGA board we are setting the high cursor byte.
   outb(0x3D5, cursorLocation >> 8); // Send the high cursor byte.
   outb(0x3D4, 15);                  // Tell the VGA board we are setting the low cursor byte.
   outb(0x3D5, cursorLocation);      // Send the low cursor byte.
}

// Clears the screen, by copying lots of spaces to the framebuffer.
void monitor_clear()
{
   // Make an attribute byte for the default colours
   u8int attributeByte = (0 /*black*/ << 4) | (15 /*white*/ & 0x0F);
   u16int blank = 0x20 /* space */ | (attributeByte << 8);

   int i;
   for (i = 0; i < 80*25; i++)
   {
       video_memory[i] = blank;
   }

   // Move the hardware cursor back to the start.
   cursor_x = 0;
   cursor_y = 0;
   move_cursor();
}

// Writes a single character out to the screen.
void monitor_put(char c)
{
   // The background colour is black (0), the foreground is white (15).
   u8int backColour = 0;
   u8int foreColour = 15;

   // The attribute byte is made up of two nibbles - the lower being the
   // foreground colour, and the upper the background colour.
   u8int  attributeByte = (backColour << 4) | (foreColour & 0x0F);
   // The attribute byte is the top 8 bits of the word we have to send to the
   // VGA board.
   u16int attribute = attributeByte << 8;
   u16int *location;

   // Handle a backspace, by moving the cursor back one space
   if (c == 0x08 && cursor_x)
   {
       cursor_x--;
   }

   // Handle a tab by increasing the cursor's X, but only to a point
   // where it is divisible by 8.
   else if (c == 0x09)
   {
       cursor_x = (cursor_x+8) & ~(8-1);
   }

   // Handle carriage return
   else if (c == '\r')
   {
       cursor_x = 0;
   }

   // Handle newline by moving cursor back to left and increasing the row
   else if (c == '\n')
   {
       cursor_x = 0;
       cursor_y++;
   }
   // Handle any other printable character.
   else if(c >= ' ')
   {
       location = video_memory + (cursor_y*80 + cursor_x);
       *location = c | attribute;
       cursor_x++;
   }

   // Check if we need to insert a new line because we have reached the end
   // of the screen.
   if (cursor_x >= 80)
   {
       cursor_x = 0;
       cursor_y ++;
   }

   // Scroll the screen if needed.
   scroll();
   // Move the hardware cursor.
   move_cursor();
}

// Outputs a null-terminated ASCII string to the monitor.
void monitor_write(char *c)
{
   int i = 0;
   while (c[i])
   {
       monitor_put(c[i++]);
   }
}

#endif // MONITOR_H

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In file included from Source Files/kernel.c:2:
/home/gulshan/Documents/OS/monitor.h: In function ‘scroll’:
/home/gulshan/Documents/OS/monitor.h:43: error: invalid storage class for function ‘move_cursor’
/home/gulshan/Documents/OS/monitor.h: In function ‘monitor_put’:
/home/gulshan/Documents/OS/monitor.h:114: warning: assignment from incompatible pointer type
Source Files/kernel.c: In function ‘scroll’:
Source Files/kernel.c:9: error: expected declaration or statement at end of input
Source Files/kernel.c: At top level:
Source Files/kernel.c:5: warning: unused parameter ‘mbd’
Source Files/kernel.c:5: warning: unused parameter ‘magic’

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       // The cursor should now be on the last line.
       cursor_y = 24;
   }

} // <- You forgot to add this.

// Updates the hardware cursor.
static void move_cursor()

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Source Files/kernel.h:1: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘default_console’
Source Files/kernel.c:7: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘:’ token
Source Files/kernel.c:14: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘:’ token

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class default_console
void default_console::default_console()
void default_console::clear()