Bootloader HelloWorld

/*
* https://stackoverflow.com/questions/32931063/write-a-simple-bootloader-helloworld-error-function-print-string
*/

asm(".code16gcc");
asm("jmpl $0x0000, $main\n");

void getch();
void cout(const char* str);

void main()
{
    asm volatile("xor %ax, %ax\n");
    asm volatile("mov %ax, %ds\n");

    cout("BootLoader\n\r");
    cout("Hello World\n\n\r");
    cout("Press any keys to continue");
    getch();
    cout("\n\n\rDone\n\r");
    cout("You can now shutdown the computer");

    asm volatile("cli\n");
    asm volatile("hlt\n");
}

void getch()
{
     asm volatile("xorw %ax, %ax\n" "int $0x16\n");
}

void cout(const char* str)
{
    while(*str)
    {
        asm volatile("int $0x10" : : "a"(0x0e00 | *str), "b"(0x0007));
        ++str;
    }
}