;******************************************************************************
;* File Name          : startup_stm32l021xx.s
;* Author             : MCD Application Team
;* Description        : STM32l021xx Devices vector table for MDK-ARM toolchain.
;*                      This module performs:
;*                      - Set the initial SP
;*                      - Set the initial PC == Reset_Handler
;*                      - Set the vector table entries with the exceptions ISR address
;*                      - Branches to __main in the C library (which eventually
;*                        calls main()).
;*                      After Reset the Cortex-M0+ processor is in Thread mode,
;*                      priority is Privileged, and the Stack is set to Main.
;******************************************************************************
;* @attention
;*
;* Copyright (c) 2016 STMicroelectronics.
;* All rights reserved.
;*
;* This software is licensed under terms that can be found in the LICENSE file
;* in the root directory of this software component.
;* If no LICENSE file comes with this software, it is provided AS-IS.
;*
;******************************************************************************

; Amount of memory (in bytes) allocated for Stack
; Tailor this value to your application needs
; <h> Stack Configuration
;   <o> Stack Size (in Bytes) <0x0-0xFFFFFFFF:8>
; </h>

Stack_Size      EQU     0x400

                AREA    STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem       SPACE   Stack_Size
__initial_sp


; <h> Heap Configuration
;   <o>  Heap Size (in Bytes) <0x0-0xFFFFFFFF:8>
; </h>

Heap_Size       EQU     0x200

                AREA    HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem        SPACE   Heap_Size
__heap_limit

                PRESERVE8
                THUMB


; Vector Table Mapped to Address 0 at Reset
                AREA    RESET, DATA, READONLY
                EXPORT  __Vectors
                EXPORT  __Vectors_End
                EXPORT  __Vectors_Size

__Vectors       DCD     __initial_sp              ; Top of Stack
                DCD     Reset_Handler             ; Reset Handler
                DCD     NMI_Handler               ; NMI Handler
                DCD     HardFault_Handler         ; Hard Fault Handler
                DCD     0                         ; Reserved
                DCD     0                         ; Reserved
                DCD     0                         ; Reserved
                DCD     0                         ; Reserved
                DCD     0                         ; Reserved
                DCD     0                         ; Reserved
                DCD     0                         ; Reserved
                DCD     SVC_Handler               ; SVCall Handler
                DCD     0                         ; Reserved
                DCD     0                         ; Reserved
                DCD     PendSV_Handler            ; PendSV Handler
                DCD     SysTick_Handler           ; SysTick Handler

                ; External Interrupts
                DCD     WWDG_IRQHandler                ; Window Watchdog
                DCD     PVD_IRQHandler                 ; PVD through EXTI Line detect
                DCD     RTC_IRQHandler                 ; RTC through EXTI Line
                DCD     FLASH_IRQHandler               ; FLASH
                DCD     RCC_IRQHandler                 ; RCC
                DCD     EXTI0_1_IRQHandler             ; EXTI Line 0 and 1
                DCD     EXTI2_3_IRQHandler             ; EXTI Line 2 and 3
                DCD     EXTI4_15_IRQHandler            ; EXTI Line 4 to 15
                DCD     0                              ; Reserved
                DCD     DMA1_Channel1_IRQHandler       ; DMA1 Channel 1
                DCD     DMA1_Channel2_3_IRQHandler     ; DMA1 Channel 2 and Channel 3
                DCD     DMA1_Channel4_5_IRQHandler     ; DMA1 Channel 4 and Channel 5
                DCD     ADC1_COMP_IRQHandler           ; ADC1, COMP1
                DCD     LPTIM1_IRQHandler              ; LPTIM1
                DCD     0                              ; Reserved
                DCD     TIM2_IRQHandler                ; TIM2
                DCD     0                              ; Reserved
                DCD     0                              ; Reserved
                DCD     0                              ; Reserved
                DCD     0                              ; Reserved
                DCD     TIM21_IRQHandler               ; TIM21
                DCD     0                              ; Reserved
                DCD     0                              ; Reserved
                DCD     I2C1_IRQHandler                ; I2C1
                DCD     0                              ; Reserved
                DCD     SPI1_IRQHandler                ; SPI1
                DCD     0                              ; Reserved
                DCD     0                              ; Reserved
                DCD     USART2_IRQHandler              ; USART2
                DCD     AES_LPUART1_IRQHandler         ; LPUART1
                DCD     0                              ; Reserved
                DCD     0                              ; Reserved
   
__Vectors_End

__Vectors_Size  EQU  __Vectors_End - __Vectors

                AREA    |.text|, CODE, READONLY

; Reset handler routine
Reset_Handler    PROC
                 EXPORT  Reset_Handler                 [WEAK]
        IMPORT  __main
        IMPORT  SystemInit

        LDR     R0, =__initial_sp          ; set stack pointer
        MSR     MSP, R0

;;Check if boot space corresponds to system memory

        LDR R0,=0x00000004
        LDR R1, [R0]
        LSRS R1, R1, #24
        LDR R2,=0x1F
        CMP R1, R2

        BNE ApplicationStart

;; SYSCFG clock enable

        LDR R0,=0x40021034
        LDR R1,=0x00000001
        STR R1, [R0]

;; Set CFGR1 register with flash memory remap at address 0

        LDR R0,=0x40010000
        LDR R1,=0x00000000
        STR R1, [R0]

ApplicationStart
                 LDR     R0, =SystemInit
                 BLX     R0
                 LDR     R0, =__main
                 BX      R0
                 ENDP

; Dummy Exception Handlers (infinite loops which can be modified)

NMI_Handler     PROC
                EXPORT  NMI_Handler                    [WEAK]
                B       .
                ENDP
HardFault_Handler\
                PROC
                EXPORT  HardFault_Handler              [WEAK]
                B       .
                ENDP
SVC_Handler     PROC
                EXPORT  SVC_Handler                    [WEAK]
                B       .
                ENDP
PendSV_Handler  PROC
                EXPORT  PendSV_Handler                 [WEAK]
                B       .
                ENDP
SysTick_Handler PROC
                EXPORT  SysTick_Handler                [WEAK]
                B       .
                ENDP

Default_Handler PROC

                EXPORT  WWDG_IRQHandler                [WEAK]
                EXPORT  PVD_IRQHandler                 [WEAK]
                EXPORT  RTC_IRQHandler                 [WEAK]
                EXPORT  FLASH_IRQHandler               [WEAK]
                EXPORT  RCC_IRQHandler                 [WEAK]
                EXPORT  EXTI0_1_IRQHandler             [WEAK]
                EXPORT  EXTI2_3_IRQHandler             [WEAK]
                EXPORT  EXTI4_15_IRQHandler            [WEAK]
                EXPORT  DMA1_Channel1_IRQHandler       [WEAK]
                EXPORT  DMA1_Channel2_3_IRQHandler     [WEAK]
                EXPORT  DMA1_Channel4_5_IRQHandler     [WEAK]
                EXPORT  ADC1_COMP_IRQHandler           [WEAK]
                EXPORT  LPTIM1_IRQHandler              [WEAK]
                EXPORT  TIM2_IRQHandler                [WEAK]
                EXPORT  TIM21_IRQHandler               [WEAK]
                EXPORT  I2C1_IRQHandler                [WEAK]
                EXPORT  SPI1_IRQHandler                [WEAK]
                EXPORT  USART2_IRQHandler              [WEAK]
                EXPORT  AES_LPUART1_IRQHandler         [WEAK]

WWDG_IRQHandler
PVD_IRQHandler
RTC_IRQHandler
FLASH_IRQHandler
RCC_IRQHandler
EXTI0_1_IRQHandler
EXTI2_3_IRQHandler
EXTI4_15_IRQHandler
DMA1_Channel1_IRQHandler
DMA1_Channel2_3_IRQHandler
DMA1_Channel4_5_IRQHandler
ADC1_COMP_IRQHandler 
LPTIM1_IRQHandler
TIM2_IRQHandler
TIM21_IRQHandler
I2C1_IRQHandler
SPI1_IRQHandler
USART2_IRQHandler
AES_LPUART1_IRQHandler

                B       .

                ENDP

                ALIGN

;*******************************************************************************
; User Stack and Heap initialization
;*******************************************************************************
                 IF      :DEF:__MICROLIB
                
                 EXPORT  __initial_sp
                 EXPORT  __heap_base
                 EXPORT  __heap_limit
                
                 ELSE
                
                 IMPORT  __use_two_region_memory
                 EXPORT  __user_initial_stackheap
                 
__user_initial_stackheap

                 LDR     R0, =  Heap_Mem
                 LDR     R1, =(Stack_Mem + Stack_Size)
                 LDR     R2, = (Heap_Mem +  Heap_Size)
                 LDR     R3, = Stack_Mem
                 BX      LR

                 ALIGN

                 ENDIF

                 END