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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Linus Nielsen Feltzing
*
* Arm bootloader and startup code based on startup.s from the iPodLinux loader
*
* Copyright (c) 2003, Daniel Palffy (dpalffy (at) rainstorm.org)
* Copyright (c) 2005, Bernard Leach <leachbj@bouncycastle.org>
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "cpu.h"
.section .init.text,"ax",%progbits
.global start
start:
msr cpsr, #0xd3 /* enter supervisor mode, disable IRQ/FIQ */
#ifndef CREATIVE_ZVx
/* Copy exception handler code to address 0 */
ldr r2, =_vectorsstart
ldr r3, =_vectorsend
ldr r4, =_vectorscopy
1:
cmp r3, r2
ldrhi r5, [r4], #4
strhi r5, [r2], #4
bhi 1b
#endif
/* Disable data and instruction cache, high vectors (at 0xffff0000 instead of 0x00000000) */
mrc p15, 0, r0, c1, c0, 0
/* clear bits 13, 9:8 (--VI --RS) */
bic r0, r0, #0x00003300
/* clear bits 7, 2:0 (B--- -C-M) */
bic r0, r0, #0x00000085
/* make sure bit 2 (A) Align is set */
orr r0, r0, #0x00000002
mcr p15, 0, r0, c1, c0, 0
#if !defined(STUB)
/* Zero out IBSS */
ldr r2, =_iedata
ldr r3, =_iend
mov r4, #0
1:
cmp r3, r2
strhi r4, [r2], #4
bhi 1b
#ifndef CREATIVE_ZVx
/* Copy the IRAM */
ldr r2, =_iramcopy
ldr r3, =_iramstart
ldr r4, =_iramend
1:
cmp r4, r3
ldrhi r5, [r2], #4
strhi r5, [r3], #4
bhi 1b
#endif
#endif /* !STUB */
/* Initialise bss section to zero */
ldr r2, =_edata
ldr r3, =_end
mov r4, #0
bsszero:
cmp r3, r2
strhi r4, [r2], #4
bhi bsszero
/* Set up some stack and munge it with 0xdeadbeef */
ldr sp, =stackend
mov r3, sp
ldr r2, =stackbegin
ldr r4, =0xdeadbeef
stackmunge:
cmp r3, r2
strhi r4, [r2], #4
bhi stackmunge
/* Set up stack for IRQ mode */
msr cpsr_c, #0xd2 /* IRQ disabled, FIQ enabled */
ldr sp, =irq_stack
/* Set up stack for FIQ mode */
msr cpsr_c, #0xd1 /* IRQ/FIQ disabled */
ldr sp, =fiq_stack
/* Let abort and undefined modes use IRQ stack */
msr cpsr_c, #0xd7 /* IRQ/FIQ disabled */
ldr sp, =irq_stack
msr cpsr_c, #0xdb /* IRQ/FIQ disabled */
ldr sp, =irq_stack
/* Switch to supervisor mode (no IRQ) */
msr cpsr_c, #0xd3
ldr sp, =stackend
start_loc:
bl main
/* main() should never return */
/* Exception handlers. Will be copied to address 0 after memory remapping */
.section .vectors,"aw"
b start
b undef_instr_handler
b software_int_handler
b prefetch_abort_handler
b data_abort_handler
b reserved_handler
b irq_handler
b fiq_handler
.text
/* All illegal exceptions call into UIE with exception address as first
parameter. This is calculated differently depending on which exception
we're in. Second parameter is exception number, used for a string lookup
in UIE.
*/
undef_instr_handler:
sub r0, lr, #4
mov r1, #0
b UIE
/* We run supervisor mode most of the time, and should never see a software
exception being thrown. Perhaps make it illegal and call UIE?
*/
software_int_handler:
reserved_handler:
movs pc, lr
prefetch_abort_handler:
sub r0, lr, #4
mov r1, #1
b UIE
data_abort_handler:
sub r0, lr, #8
mov r1, #2
b UIE
#ifdef STUB
UIE:
b UIE
#endif
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