01_exercise/bootloader.c


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/* needs to stay the first line */
asm(".code16gcc\njmp $0, $main");

/* space for additional code */

char WRITE_CHARACTER_TTY = 0x0E; 
void put(char c) {
    short command = WRITE_CHARACTER_TTY << 8 | c;
    // volatile because there is no output, so the function might get optimized away
    asm volatile("int $0x10;"
    :: "a"(command)
    );
}


void main(void)
{   
    put('h');
    put('e');
    put('l');
    put('l');
    put('o');
}