mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-04 19:00:09 +00:00
90 lines
2.9 KiB
ArmAsm
90 lines
2.9 KiB
ArmAsm
/* Copyright (C) 1994 Free Software Foundation, Inc.
|
|
Contributed by Joel Sherrill (jsherril@redstone-emh2.army.mil),
|
|
On-Line Applications Research Corporation.
|
|
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public License as
|
|
published by the Free Software Foundation; either version 2 of the
|
|
License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If
|
|
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
|
|
Cambridge, MA 02139, USA. */
|
|
|
|
/* This file assists the board independent startup code by
|
|
* loading the proper segment register values. The values
|
|
* loaded are dependent on the FORCEBUG.
|
|
*
|
|
* NOTE: No stack has been established when this routine
|
|
* is invoked. It returns by jumping back to the start code.
|
|
*
|
|
*/
|
|
|
|
/*
|
|
* FORCEBUG loads us into a virtual address space which
|
|
* really starts at PHYSICAL_ADDRESS_BASE.
|
|
*
|
|
*/
|
|
|
|
.set PHYSICAL_ADDRESS_BASE, 0x00002000
|
|
|
|
/*
|
|
* At reset time, FORCEBUG normally has the segment selectors preloaded.
|
|
* If a human resets the instruction pointer, this will not have occurred.
|
|
* However, no guarantee can be made of the other registers if cs:ip was
|
|
* modified to restart the program. Because of this, the BSP reloads all
|
|
* segment registers (except cs) with the values they have following
|
|
* a reset.
|
|
*/
|
|
|
|
|
|
.set RESET_SS, 0x40 # initial value of stack segment register
|
|
.set RESET_DS, 0x40 # initial value of data segment register
|
|
.set RESET_ES, 0x40 # initial value of extra segment register
|
|
.set RESET_FS, 0x40 # initial value of "f" segment register
|
|
.set RESET_GS, 0x30 # initial value of "g" segment register
|
|
|
|
|
|
#define LOAD_SEGMENTS(_value,_segreg) \
|
|
movw $_value##,%ax ; \
|
|
movw %ax,##_segreg
|
|
|
|
|
|
.global _load_segments
|
|
|
|
.global _establish_stack
|
|
|
|
_load_segments:
|
|
|
|
LOAD_SEGMENTS( RESET_SS, %ss )
|
|
LOAD_SEGMENTS( RESET_DS, %ds )
|
|
LOAD_SEGMENTS( RESET_ES, %es )
|
|
LOAD_SEGMENTS( RESET_FS, %fs )
|
|
LOAD_SEGMENTS( RESET_GS, %gs )
|
|
|
|
jmp _establish_stack # return to the bsp entry code
|
|
|
|
.global _return_to_monitor
|
|
_return_to_monitor:
|
|
|
|
movb $0,%al
|
|
int $0x20 # restart FORCEbug
|
|
jmp start # FORCEbug does not reset PC
|
|
|
|
.data
|
|
|
|
.global _Do_Load_IDT
|
|
_Do_Load_IDT: .byte 1
|
|
|
|
.global _Do_Load_GDT
|
|
_Do_Load_GDT: .byte 0
|
|
|