/*-
 * Copyright (c) 2002-2018 The UbixOS Project.
 * All rights reserved.
 *
 * This was developed by Christopher W. Olsen for the UbixOS Project.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * 1) Redistributions of source code must retain the above copyright notice, this list of
 *    conditions, the following disclaimer and the list of authors.
 * 2) Redistributions in binary form must reproduce the above copyright notice, this list of
 *    conditions, the following disclaimer and the list of authors in the documentation and/or
 *    other materials provided with the distribution.
 * 3) Neither the name of the UbixOS Project nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

.globl _start
.text
.code32
_start:
  movw  $0x1234,0x472
  pushl %ebp
  movl  %esp,%ebp
  pushl $0x00000002
  popfl
  /* Clear the BSS */
  movl  $(_end),%ecx
  movl  $(__bss_start),%edi
  subl  %edi,%ecx
  xorl  %eax,%eax
  cld
  rep
  stosb
 
  /* Load GDT */
  lgdtl (loadGDT)
  mov   $0x10,%eax 
  mov   %eax,%ds
  mov   %eax,%es
  mov   %eax,%fs
  mov   %eax,%gs
  mov   %eax,%ss
  mov   $kStack,%eax
  addl  $0x2000,%eax
  mov   %esp,%edx
  mov   %eax,%esp
  mov   %eax,%ebp 
  mov   $0x18,%ax
  lldt  %ax
  mov   $0x20,%ax
  ltr   %ax
  ljmp  $0x08,$start_next
start_next:
  push 8(%edx)
  call kmain

.data
.comm kStack,0x2000

/***
 END
 ***/