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Code: Select all

.global loader                 # making entry point visible to linker

# setting up the Multiboot header - see GRUB docs for details
.set ALIGN,    1<<0             # align loaded modules on page boundaries
.set MEMINFO,  1<<1             # provide memory map
.set FLAGS,    ALIGN | MEMINFO  # this is the Multiboot 'flag' field
.set MAGIC,    0x1BADB002       # 'magic number' lets bootloader find the header
.set CHECKSUM, -(MAGIC + FLAGS) # checksum required

.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM

# reserve initial kernel stack space
.set STACKSIZE, 0x4000          # that is, 16k.
.comm stack, STACKSIZE, 32      # reserve 16k stack on a quadword boundary

loader:
  mov   $(stack + STACKSIZE), %esp

  push  $15
  call  txt_clear	# Clears screen

  mov   $2, %AH
  mov   $0, %BH
  mov   $0, %DH
  mov   $0, %DL
  int   $0x10        # Moves cursor

  #push  %eax
  #push  %ebx

  #call  kmain            # call kernel proper

  cli
hang:
  hlt                    # halt machine should kernel return
  jmp   hang

Code: Select all

void move_csr(void)
{
    unsigned temp;

    /* The equation for finding the index in a linear
    *  chunk of memory can be represented by:
    *  Index = [(y * width) + x] */
    temp = csr_y * 80 + csr_x;

    /* This sends a command to indicies 14 and 15 in the
    *  CRT Control Register of the VGA controller. These
    *  are the high and low bytes of the index that show
    *  where the hardware cursor is to be 'blinking'. To
    *  learn more, you should look up some VGA specific
    *  programming documents. A great start to graphics:
    *  http://www.brackeen.com/home/vga */
    outportb(0x3D4, 14);
    outportb(0x3D5, temp >> 8);
    outportb(0x3D4, 15);
    outportb(0x3D5, temp);
}