e0f8c31216
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18775 a1c6a512-1295-4272-9138-f99709370657
131 lines
3.3 KiB
ArmAsm
131 lines
3.3 KiB
ArmAsm
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2008 by Marcoen Hirschberg
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "config.h"
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#include "cpu.h"
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.section .init.text,"ax",%progbits
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.global start
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start:
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/* Exception vectors */
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b newstart
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b undef_instr_handler
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b software_int_handler
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b prefetch_abort_handler
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b data_abort_handler
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b reserved_handler
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b irq_handler
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b fiq_handler
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.word 0x43554644 /* DFUC */
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newstart:
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msr cpsr_c, #0xd3 /* enter supervisor mode, disable IRQ/FIQ */
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#if 0
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/* set PWRON to 1 */
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ldr r1, =0x3CF00014
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ldr r2, [r1]
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orr r2, r2, #0x8
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str r2, [r1]
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ldr r1, =0x3CF00010
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ldr r2, [r1]
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bic r2, r2, #0xf000
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orr r2, r2, #0x1000
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str r2, [r1]
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#endif
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/* Initialise bss section to zero */
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ldr r2, =_edata
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ldr r3, =_end
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mov r4, #0
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1:
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cmp r3, r2
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strhi r4, [r2], #4
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bhi 1b
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/* Set up some stack and munge it with 0xdeadbeef */
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ldr sp, =stackend
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ldr r2, =stackbegin
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ldr r3, =0xdeadbeef
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1:
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cmp sp, r2
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strhi r3, [r2], #4
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bhi 1b
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/* Set up stack for IRQ mode */
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msr cpsr_c, #0xd2
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ldr sp, =irq_stack
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/* Set up stack for FIQ mode */
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msr cpsr_c, #0xd1
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ldr sp, =fiq_stack
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/* Let abort and undefined modes use IRQ stack */
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msr cpsr_c, #0xd7
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ldr sp, =irq_stack
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msr cpsr_c, #0xdb
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ldr sp, =irq_stack
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/* Switch back to supervisor mode */
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msr cpsr_c, #0xd3
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bl main
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.text
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/* .global UIE*/
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/* All illegal exceptions call into UIE with exception address as first
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* parameter. This is calculated differently depending on which exception
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* we're in. Second parameter is exception number, used for a string lookup
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* in UIE. */
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undef_instr_handler:
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mov r0, lr
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mov r1, #0
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b UIE
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/* We run supervisor mode most of the time, and should never see a software
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* exception being thrown. Perhaps make it illegal and call UIE? */
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software_int_handler:
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reserved_handler:
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movs pc, lr
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prefetch_abort_handler:
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sub r0, lr, #4
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mov r1, #1
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b UIE
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data_abort_handler:
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sub r0, lr, #8
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mov r1, #2
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b UIE
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/* 256 words of IRQ stack */
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.space 256*4
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irq_stack:
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/* 256 words of FIQ stack */
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.space 256*4
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fiq_stack:
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end:
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/*.word 0xA5A5A5A5
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.word 0x5A5A5A5A*/
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