08fb3f6574
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29808 a1c6a512-1295-4272-9138-f99709370657
117 lines
3.3 KiB
ArmAsm
117 lines
3.3 KiB
ArmAsm
/***************************************************************************
|
|
* __________ __ ___.
|
|
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
|
|
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
|
|
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
|
|
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
|
|
* \/ \/ \/ \/ \/
|
|
* $Id$
|
|
*
|
|
* Copyright (C) 2011 by Amaury Pouly
|
|
*
|
|
* 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 .vectors,"ax",%progbits
|
|
.code 32
|
|
.global start
|
|
start:
|
|
/* most handlers are in DRAM which is too far away for a relative jump */
|
|
ldr pc, =newstart
|
|
ldr pc, =undef_instr_handler
|
|
ldr pc, =software_int_handler
|
|
ldr pc, =prefetch_abort_handler
|
|
ldr pc, =data_abort_handler
|
|
ldr pc, =reserved_handler
|
|
ldr pc, =irq_handler
|
|
ldr pc, =fiq_handler
|
|
|
|
.text
|
|
newstart:
|
|
msr cpsr_c, #0xd3 /* enter supervisor mode, disable IRQ/FIQ */
|
|
/* Set up some stack and munge it with 0xdeadbeef */
|
|
ldr sp, =stackend
|
|
ldr r2, =stackbegin
|
|
ldr r3, =0xdeadbeef
|
|
1:
|
|
cmp sp, r2
|
|
strhi r3, [r2], #4
|
|
bhi 1b
|
|
|
|
/* Set up stack for IRQ mode */
|
|
msr cpsr_c, #0xd2
|
|
ldr sp, =irq_stack
|
|
|
|
/* Set up stack for FIQ mode */
|
|
msr cpsr_c, #0xd1
|
|
ldr sp, =fiq_stack
|
|
|
|
/* Let abort and undefined modes use IRQ stack */
|
|
msr cpsr_c, #0xd7
|
|
ldr sp, =irq_stack
|
|
msr cpsr_c, #0xdb
|
|
ldr sp, =irq_stack
|
|
|
|
/* Switch back to supervisor mode */
|
|
msr cpsr_c, #0xd3
|
|
|
|
/* Disable MMU, disable caching and buffering;
|
|
* use low exception range address (the core uses high range by default) */
|
|
mrc p15, 0, r0, c1, c0, 0
|
|
ldr r1, =0x3005
|
|
bic r0, r1
|
|
mcr p15, 0, r0, c1, c0, 0
|
|
|
|
/* Jump to main */
|
|
bl main
|
|
1:
|
|
b 1b
|
|
|
|
/* 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 @ r0 points to the faulty ARM instruction
|
|
#ifdef USE_THUMB
|
|
mrs r1, spsr
|
|
tst r1, #(1<<5) @ T bit set ?
|
|
subne r0, lr, #2 @ if yes, r0 points to the faulty THUMB instruction
|
|
#endif /* USE_THUMB */
|
|
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
|
|
|
|
/* 256 words of IRQ stack */
|
|
.space 256*4
|
|
irq_stack:
|
|
|
|
/* 256 words of FIQ stack */
|
|
.space 256*4
|
|
fiq_stack:
|
|
|
|
end:
|