sos-code-article10/extra/sos_bsect.lds

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2018-07-13 17:13:10 +02:00
/* Copyright (C) 2004, David Decotigny
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
*/
SECTIONS
{
/* ***********************************************
* The bootsector is here. We link it against the remaining of the kernel
* in order to automatically figure out its size that must be loaded
* from file to memory (see the load_size definition below)
*/
/* If we use one, we put the boot sector here. We don't set its
* address to 0x7c000 (aka 0x7c00:0), since it reloads itself to
* 0x9f000, causing the 0x7c000 address to be meaningless too. So we
* chose to pretend that the address is 0x0, and to make a little
* address arithmetic in bootsect.S */
.bootsect 0x0 :
{
/* The code for the boot sector goes here */
*(.bootsect);
/* The load_size symbol contains the size of the area (in
* sectors, aka 512 Bytes) that the boot sector should copy from
* the disk. The bss section is not included since it uses 0
* bytes on disk. This variable is short (16b) because it is used
* by the bootsector in real mode, and this is enough because
* our boot sector cannot transfer more than 1264 sectors (see
* bootsector sources) */
load_size = .;
SHORT((__e_load - __b_load + 511) >> 9);
/* ---> This is equivalent to ceil( (__e_load - __b_load) / 512 ) */
/* At offsets 511 and 512, we set the boot sector signature (AA55h) */
. = 0x1fe;
SHORT(0xAA55);
}
}
/* This is to avoid a cut/paste here. Please notice that a multiboot
* section WILL be inserted, which is NOT mandatory (we could have
* removed it without getting into trouble). Please note however that
* the *.bin files will NOT be multiboot compatible (they are not in ELF
* format): they are expected to be directly booted by the BIOS (or
* by the "chainloader" command of Grub). */
INCLUDE ../support/sos.lds
/* We overload the entry set in sos.lds, just to avoid an ld warning */
ENTRY(sos_main);