Moving text mode cursor not working

Question

I have been working on moving the text mode cursor in the operating system I am currently developing. I am having trouble getting it to show up at all. Here is the code that

Answer 1

Your outb function has port and value in the wrong places. Instead of:

asm volatile ( "outb %0, %1" : : "a"(value), "Nd"(port) );

Try:

asm volatile ("outb %1, %0" : : "dN" (port), "a" (value));

Hope it helps :)

Answer 2

You select wrong VGA registers. You have to use 0x0F for low and 0x0E for high (you have 0x0A for both).

Edit: In case your cursor is disabled, this is how to enable it:

void enable_cursor() {
    outb(0x3D4, 0x0A);
    char curstart = inb(0x3D5) & 0x1F; // get cursor scanline start

    outb(0x3D4, 0x0A);
    outb(0x3D5, curstart | 0x20); // set enable bit
}

Also check this link for list of register numbers and usages.

Edit2: Your cursor location variable is not wide enough to store the cursor location. unsigned char cursor_loc should be unsigned short cursor_loc.