I am totally new to OS dev and I found an article on the web about making a simple OShttp://www.rohitab.com/discuss/lofivers ... 24959.html
I downloaded the attachment, compiled the OS and ran the ISO on my virtual pc and it went fine. I modified the kernel.c (code below) so that it printed an extra line saying goodbye, but it doesn't show up.
The code for kernel.c is below and kernel.h and screen.c are attached.
Code: Select all
#include "kernel.h"
int strlen(string str);
void dec2bin(dword decimal, int prefix);
void drawdesktop(byte ch, char fore, char back);
void drawwindow(string title, int xpos, int ypos, int width, int height, char fore, char back);
void kernel(void) // kernel entry point
{
drawdesktop(177, COLOR_WHITE, COLOR_BLUE);
drawwindow(" Simple OS Example - by Napalm ", 4, 4, 72, 16, COLOR_LTWHITE, COLOR_BLUE);
putsnocr("Welcome to this example! ");
/* I put another putsnocr line here but it didnt show up only "Welcome to this example" showed */
hidecursor();
dword value = 0xDEADBEEF;
while(1){
// display value in decimal
gotoxy(6, 9);
dword decimal = value;
char base[10];
int i = 0;
while(decimal > 0){
base[i++] = '0' + (decimal % 10);
decimal /= 10;
}
while(i-- > 0) putch(base[i]);
// display value in hex
gotoxy(6, 10);
putsnocr("0x");
for(int i = 28; i > -1; i -= 4){
byte nibble = ((value >> i) & 0x0F);
if(nibble < 10) putch('0' + nibble);
else putch('A' + (nibble - 10));
}
// display value in binary
gotoxy(6, 11);
dec2bin(value, 32);
value++;
}
}
int strlen(string str) // simple string length
{
string end = str;
while(*end++);
return (end - str);
}
void drawdesktop(byte ch, char fore, char back)
{
// clear screen with foreground and background
// and also with desired character
settextcolor(fore, back);
cls(ch);
}
// decimal to binary
void dec2bin(dword decimal, int prefix)
{
dword j = 0;
for(int i = prefix; i >= 0; --i, j = ((decimal & (1 << i)) >> i))
if(prefix || j) prefix = putch('0' + j);
}
void drawwindow(string title, int xpos, int ypos, int width, int height, char fore, char back)
{
int xextent = (xpos + width - 1), yextent = (ypos + height - 1);
// draw window
for(int y = ypos; y <= yextent; y++){
settextcolor(fore, back);
gotoxy(xpos, y);
if(y == ypos){ // draw top caption bar
settextcolor(COLOR_LTYELLOW, COLOR_RED);
for(int x = xpos; x <= xextent; x++){
if(x == xpos) putch(213);
else if(x == xextent) putch(254);
else putch(205);
}
gotoxy(xpos + ((width - strlen(title)) / 2), y);
putsnocr(title);
}else if(y < yextent){ // draw middle lines
for(int x = xpos; x <= xextent; x++){
if(x == xpos || x == xextent) putch(179);
else putch(' ');
}
}else{ // draw bottom edge
for(int x = xpos; x <= xextent; x++){
if(x == xpos) putch(192);
else if(x == xextent) putch(217);
else putch(196);
}
}
}
// draw vertical shadow
for(int y = ypos; y <= yextent; y++){
gotoxy(xextent + 1, y + 1);
settextcolor(COLOR_WHITE, COLOR_BLACK);
putch(177);
}
// draw horizontal shadow
for(int x = xpos; x <= xextent; x++){
gotoxy(x + 1, yextent + 1);
settextcolor(COLOR_WHITE, COLOR_BLACK);
putch(177);
}
// position cursor inside window
gotoxy(xpos + 2, ypos + 2);
settextcolor(fore, back);
}Thanks for your time
HLA91
