/* File: startup_armv6-m.S
* Purpose: startup file for armv6-m architecture devices.
* Should be used with GCC for ARM Embedded Processors
* Version: V2.00
* Date: 16 November 2015
*
*/
/* Copyright (c) 2011 - 2015 ARM LIMITED
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
- 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.
- Neither the name of ARM 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 COPYRIGHT HOLDERS AND 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.
---------------------------------------------------------------------------*/
.syntax unified
.arch armv6-m
.section .stack
.align 3
#ifdef __STACK_SIZE
.equ Stack_Size, __STACK_SIZE
#else
.equ Stack_Size, 0x00000400
#endif
.globl __StackTop
.globl __StackLimit
__StackLimit:
.space Stack_Size
.size __StackLimit, . - __StackLimit
__StackTop:
.size __StackTop, . - __StackTop
.section .heap
.align 3
#ifdef __HEAP_SIZE
.equ Heap_Size, __HEAP_SIZE
#else
.equ Heap_Size, 0x00000C00
#endif
.globl __HeapBase
.globl __HeapLimit
__HeapBase:
.if Heap_Size
.space Heap_Size
.endif
.size __HeapBase, . - __HeapBase
__HeapLimit:
.size __HeapLimit, . - __HeapLimit
.section .vectors
.align 2
.globl __Vectors
__Vectors:
.long __StackTop /* Top of Stack */
.long Reset_Handler /* Reset Handler */
.long NMI_Handler /* NMI Handler */
.long HardFault_Handler /* Hard Fault Handler */
.long 0 /* Reserved */
.long 0 /* Reserved */
.long 0 /* Reserved */
.long 0 /* Reserved */
.long 0 /* Reserved */
.long 0 /* Reserved */
.long 0 /* Reserved */
.long SVC_Handler /* SVCall Handler */
.long 0 /* Reserved */
.long 0 /* Reserved */
.long PendSV_Handler /* PendSV Handler */
.long SysTick_Handler /* SysTick Handler */
.size __Vectors, . - __Vectors
.text
.thumb
.thumb_func
.align 1
.globl Reset_Handler
.type Reset_Handler, %function
Reset_Handler:
/* Firstly it copies data from read only memory to RAM. There are two schemes
* to copy. One can copy more than one sections. Another can only copy
* one section. The former scheme needs more instructions and read-only
* data to implement than the latter.
* Macro __STARTUP_COPY_MULTIPLE is used to choose between two schemes. */
#ifdef __STARTUP_COPY_MULTIPLE
/* Multiple sections scheme.
*
* Between symbol address __copy_table_start__ and __copy_table_end__,
* there are array of triplets, each of which specify:
* offset 0: LMA of start of a section to copy from
* offset 4: VMA of start of a section to copy to
* offset 8: size of the section to copy. Must be multiply of 4
*
* All addresses must be aligned to 4 bytes boundary.
*/
ldr r4, =__copy_table_start__
ldr r5, =__copy_table_end__
.L_loop0:
cmp r4, r5
bge .L_loop0_done
ldr r1, [r4]
ldr r2, [r4, #4]
ldr r3, [r4, #8]
.L_loop0_0:
subs r3, #4
blt .L_loop0_0_done
ldr r0, [r1, r3]
str r0, [r2, r3]
b .L_loop0_0
.L_loop0_0_done:
adds r4, #12
b .L_loop0
.L_loop0_done:
#else
/* Single section scheme.
*
* The ranges of copy from/to are specified by following symbols
* __etext: LMA of start of the section to copy from. Usually end of text
* __data_start__: VMA of start of the section to copy to
* __data_end__: VMA of end of the section to copy to
*
* All addresses must be aligned to 4 bytes boundary.
*/
ldr r1, =__etext
ldr r2, =__data_start__
ldr r3, =__data_end__
subs r3, r2
ble .L_loop1_done
.L_loop1:
subs r3, #4
ldr r0, [r1,r3]
str r0, [r2,r3]
bgt .L_loop1
.L_loop1_done:
#endif /*__STARTUP_COPY_MULTIPLE */
/* This part of work usually is done in C library startup code. Otherwise,
* define this macro to enable it in this startup.
*
* There are two schemes too. One can clear multiple BSS sections. Another
* can only clear one section. The former is more size expensive than the
* latter.
*
* Define macro __STARTUP_CLEAR_BSS_MULTIPLE to choose the former.
* Otherwise efine macro __STARTUP_CLEAR_BSS to choose the later.
*/
#ifdef __STARTUP_CLEAR_BSS_MULTIPLE
/* Multiple sections scheme.
*
* Between symbol address __copy_table_start__ and __copy_table_end__,
* there are array of tuples specifying:
* offset 0: Start of a BSS section
* offset 4: Size of this BSS section. Must be multiply of 4
*/
ldr r3, =__zero_table_start__
ldr r4, =__zero_table_end__
.L_loop2:
cmp r3, r4
bge .L_loop2_done
ldr r1, [r3]
ldr r2, [r3, #4]
movs r0, 0
.L_loop2_0:
subs r2, #4
blt .L_loop2_0_done
str r0, [r1, r2]
b .L_loop2_0
.L_loop2_0_done:
adds r3, #8
b .L_loop2
.L_loop2_done:
#elif defined (__STARTUP_CLEAR_BSS)
/* Single BSS section scheme.
*
* The BSS section is specified by following symbols
* __bss_start__: start of the BSS section.
* __bss_end__: end of the BSS section.
*
* Both addresses must be aligned to 4 bytes boundary.
*/
ldr r1, =__bss_start__
ldr r2, =__bss_end__
movs r0, 0
subs r2, r1
ble .L_loop3_done
.L_loop3:
subs r2, #4
str r0, [r1, r2]
bgt .L_loop3
.L_loop3_done:
#endif /* __STARTUP_CLEAR_BSS_MULTIPLE || __STARTUP_CLEAR_BSS */
#ifndef __NO_SYSTEM_INIT
bl SystemInit
#endif
#ifndef __START
#define __START _start
#endif
bl __START
.pool
.size Reset_Handler, . - Reset_Handler
.align 1
.thumb_func
.weak Default_Handler
.type Default_Handler, %function
Default_Handler:
bkpt #0
b .
.size Default_Handler, . - Default_Handler
/* Macro to define default handlers. Default handler
* will be weak symbol and just dead loops. They can be
* overwritten by other handlers */
.macro def_irq_handler handler_name
.weak \handler_name
.set \handler_name, Default_Handler
.endm
def_irq_handler NMI_Handler
def_irq_handler HardFault_Handler
def_irq_handler SVC_Handler
def_irq_handler PendSV_Handler
def_irq_handler SysTick_Handler
.end
