boot/freeldr/freeldr/arch/i386/linux.S

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 1998-2002  Brian Palmer  <brianp@sginet.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License along
  16  *  with this program; if not, write to the Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <asm.inc>
  21 #include <arch/pc/x86common.h>
  22
  23 EXTERN i386CallRealMode:PROC
  24
  25 .code32
  26
  27 /*
  28  *  VOID BootOldLinuxKernel(ULONG KernelSize);
  29  */
  30 PUBLIC _BootOldLinuxKernel
  31 _BootOldLinuxKernel:
  32
  33         /* First we have to copy the kernel down from 0x100000 to 0x10000 */
  34         /* The reason we can overwrite low memory is because this code */
  35         /* executes between 0000:8000 and 0000:FFFF. That leaves space for */
  36         /* 32k of code before we start interfering with Linux kernel address space. */
  37
  38         /* Get KernelSize in ECX and move the kernel down */
  39         mov ecx, [esp + 4]
  40         mov esi, HEX(100000)
  41         mov edi, HEX(10000)
  42         rep movsb
  43
  44     /* Fall through */
  45
  46 PUBLIC _BootNewLinuxKernel
  47 _BootNewLinuxKernel:
  48
  49     mov bx, FNID_BootLinuxKernel
  50     call i386CallRealMode
  51
  52     /* We should never get here */
  53     int 3
  54
  55 END