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LibrePilot/flight/PiOS/STM32F2xx/startup_stm32f2xx_FreeRTOS.S
2011-08-12 21:28:02 -05:00

189 lines
5.4 KiB
ArmAsm

/**
******************************************************************************
* @file startup_stm32f2xx.s
* @author MCD Application Team / Michael Smith: Vector table for FreeRTOS
* @version V0.1
* @date 03/24/2011
* @brief STM32F2xx High Density Devices vector table for GCC toolchain.
* Derived from startup_stm32f10x_HD_OP.s
*
* This module performs:
* - Set the initial SP
* - Set the initial PC == Reset_Handler,
* - Set the vector table entries with the exceptions ISR address
* - Configure the clock system and the external SRAM mounted on
* STM3210E-EVAL board to be used as data memory (optional,
* to be enabled by user)
* - Branches to main in the C library (which eventually
* calls main()).
* After Reset the Cortex-M3 processor is in Thread mode,
* priority is Privileged, and the Stack is set to Main.
*******************************************************************************
* @copy
*
* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
* TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
* DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
* FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
* CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
*
* <h2><center>&copy; COPYRIGHT 2010 STMicroelectronics</center></h2>
*/
#include "pios_config.h"
.syntax unified
.cpu cortex-m3
.fpu softvfp
.thumb
.global g_pfnVectors
.global Default_Handler
.global xPortIncreaseHeapSize
.global Stack_Change
/* start address for the initialization values of the .data section.
defined in linker script */
.word _sidata
/* start address for the .data section. defined in linker script */
.word _sdata
/* end address for the .data section. defined in linker script */
.word _edata
/* start address for the .bss section. defined in linker script */
.word _sbss
/* end address for the .bss section. defined in linker script */
.word _ebss
/**
* @brief This is the code that gets called when the processor first
* starts execution following a reset event. Only the absolutely
* necessary set is performed, after which the application
* supplied main() routine is called.
* @param None
* @retval : None
*/
.section .text.Reset_Handler
.weak Reset_Handler
.type Reset_Handler, %function
Reset_Handler:
/*
* From Cortex-M3 reference manual:
* - Handler IRQ always use SP_main
* - Process use SP_main or SP_process
* Here, we will use beginning of SRAM for IRQ (SP_main)
* and end of heap for initialization (SP_process).
* Once the schedule starts, all threads will use their own stack
* from heap and NOBOBY should use SP_process again.
*/
/* Do set/reset the stack pointers */
LDR r0, =_irq_stack_top
MSR msp, r0
LDR r2, =_init_stack_top
MSR psp, r2
/* check if irq and init stack are the same */
/* if they are, we don't do stack swap */
/* and lets bypass the monitoring as well for now */
cmp r0, r2
beq SectionBssInit
/* DO
* - stay in thread process mode
* - stay in privilege level
* - use process stack
*/
movs r0, #2
MSR control, r0
ISB
/* Fill IRQ stack for watermark monitoring */
ldr r2, =_irq_stack_end
b LoopFillIRQStack
FillIRQStack:
movw r3, #0xA5A5
str r3, [r2], #4
LoopFillIRQStack:
ldr r3, = _irq_stack_top
cmp r2, r3
bcc FillIRQStack
SectionBssInit:
/* Copy the data segment initializers from flash to SRAM */
movs r1, #0
b LoopCopyDataInit
CopyDataInit:
ldr r3, =_sidata
ldr r3, [r3, r1]
str r3, [r0, r1]
adds r1, r1, #4
LoopCopyDataInit:
ldr r0, =_sdata
ldr r3, =_edata
adds r2, r0, r1
cmp r2, r3
bcc CopyDataInit
ldr r2, =_sbss
b LoopFillZerobss
/* Zero fill the bss segment. */
FillZerobss:
movs r3, #0
str r3, [r2], #4
LoopFillZerobss:
ldr r3, = _ebss
cmp r2, r3
bcc FillZerobss
/* Call the application's entry point.*/
bl main
/* will never return here */
bx lr
.size Reset_Handler, .-Reset_Handler
/**
* @brief This is the code that swaps stack (from end of heap to irq_stack).
* @param None
* @retval : None
*/
.section .text.Stack_Change
.weak Stack_Change
.type Stack_Change, %function
Stack_Change:
mov r4, lr
/* Switches stack back momentarily to MSP */
movs r0, #0
msr control, r0
bx r4
.size Stack_Change, .-Stack_Change
/**
* @brief Dummy SystemInit_ExtMemCtl function
* @param None
* @retval : None
*/
.section .text.SystemInit_ExtMemCtl_Dummy,"ax",%progbits
SystemInit_ExtMemCtl_Dummy:
bx lr
.size SystemInit_ExtMemCtl_Dummy, .-SystemInit_ExtMemCtl_Dummy
/**
* @brief This is the code that gets called when the processor receives an
* unexpected interrupt. This simply enters an infinite loop, preserving
* the system state for examination by a debugger.
*
* @param None
* @retval : None
*/
.section .text.Default_Handler,"ax",%progbits
Default_Handler:
Infinite_Loop:
b Infinite_Loop
.size Default_Handler, .-Default_Handler
/* grab the vectors from the standard file */
#define INITIAL_STACK_TOP _irq_stack_top
#include "vectors_stm32f2xx.S"