/****************************************************************************
* Copyright (c) 2006 by Michael Fischer. All rights reserved.
*
* 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 and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author 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 COPYRIGHT HOLDERS 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.
*
****************************************************************************
*
* History:
*
* 31.03.06 mifi First Version
* This version based on an example from Ethernut and
* "ARM Cross Development with Eclipse" from James P. Lynch
****************************************************************************/
/*
* Some defines for the program status registers
*/
ARM_MODE_USER = 0x10 /* Normal User Mode */
ARM_MODE_FIQ = 0x11 /* FIQ Fast Interrupts Mode */
ARM_MODE_IRQ = 0x12 /* IRQ Standard Interrupts Mode */
ARM_MODE_SVC = 0x13 /* Supervisor Interrupts Mode */
ARM_MODE_ABORT = 0x17 /* Abort Processing memory Faults Mode */
ARM_MODE_UNDEF = 0x1B /* Undefined Instructions Mode */
ARM_MODE_SYS = 0x1F /* System Running in Priviledged Operating Mode */
ARM_MODE_MASK = 0x1F
I_BIT = 0x80 /* disable IRQ when I bit is set */
F_BIT = 0x40 /* disable IRQ when I bit is set */
/*
* Register Base Address
*/
.section .vectors,"ax"
.code 32
/****************************************************************************/
/* Vector table and reset entry */
/****************************************************************************/
_vectors:
ldr pc, ResetAddr /* Reset */
ldr pc, UndefAddr /* Undefined instruction */
ldr pc, SWIAddr /* Software interrupt */
ldr pc, PAbortAddr /* Prefetch abort */
ldr pc, DAbortAddr /* Data abort */
.word 0xB8A06F60
ldr pc, IRQAddr /* IRQ interrupt */
ldr pc, FIQAddr /* FIQ interrupt */
ResetAddr: .word ResetHandler
UndefAddr: .word UndefHandler
SWIAddr: .word SWIHandler
PAbortAddr: .word PAbortHandler
DAbortAddr: .word DAbortHandler
ReservedAddr: .word 0
IRQAddr: .word IRQHandler
FIQAddr: .word FIQHandler
.ltorg
.section .init, "ax"
.code 32
.global ResetHandler
.global ExitFunction
.extern main
/****************************************************************************/
/* Reset handler */
/****************************************************************************/
ResetHandler:
/*
* Wait for the oscillator is stable
*/
nop
nop
nop
nop
nop
nop
nop
nop
/*
* Setup a stack for each mode
*/
msr CPSR_c, #ARM_MODE_UNDEF | I_BIT | F_BIT /* Undefined Instruction Mode */
ldr sp, =__stack_und_end
msr CPSR_c, #ARM_MODE_ABORT | I_BIT | F_BIT /* Abort Mode */
ldr sp, =__stack_abt_end
msr CPSR_c, #ARM_MODE_FIQ | I_BIT | F_BIT /* FIQ Mode */
ldr sp, =__stack_fiq_end
msr CPSR_c, #ARM_MODE_IRQ | I_BIT | F_BIT /* IRQ Mode */
ldr sp, =__stack_irq_end
msr CPSR_c, #ARM_MODE_SVC | I_BIT | F_BIT /* Supervisor Mode */
ldr sp, =__stack_svc_end
/*
* Clear .bss section
*/
ldr r1, =__bss_start
ldr r2, =__bss_end
ldr r3, =0
bss_clear_loop:
cmp r1, r2
strne r3, [r1], #+4
bne bss_clear_loop
/*
* Jump to main
*/
mrs r0, cpsr
bic r0, r0, #I_BIT | F_BIT /* Enable FIQ and IRQ interrupt */
msr cpsr, r0
mov r0, #0 /* No arguments */
mov r1, #0 /* No arguments */
ldr r2, =main
mov lr, pc
bx r2 /* And jump... */
ExitFunction:
nop
nop
nop
b ExitFunction
/****************************************************************************/
/* Default interrupt handler */
/****************************************************************************/
UndefHandler:
b UndefHandler
SWIHandler:
b SWIHandler
PAbortHandler:
b PAbortHandler
DAbortHandler:
b DAbortHandler
IRQHandler:
b IRQHandler
FIQHandler:
b FIQHandler
.weak ExitFunction
.weak UndefHandler, PAbortHandler, DAbortHandler
.weak IRQHandler, FIQHandler
.ltorg
/*** EOF ***/
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