startup.s

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#import #vector #delete #exception #loops #include

;EN_CRP EQU 1 ; 定义是否加密芯片

INCLUDE ../ARM/LPC23xx.INC

;定义堆栈的大小
SVC_STACK_LEGTH         EQU         0x0008
FIQ_STACK_LEGTH         EQU         0
IRQ_STACK_LEGTH         EQU         0x0100
ABT_STACK_LEGTH         EQU         0
UND_STACK_LEGTH         EQU         0

NoInt EQU 0x80
NoFIQ EQU 0x40

USR32Mode   EQU 0x10
SVC32Mode   EQU 0x13
SYS32Mode   EQU 0x1f
IRQ32Mode   EQU 0x12
FIQ32Mode   EQU 0x11

STAY_IN_IAP EQU 0x1234ABCD

;引入的外部标号在这声明
    IMPORT __main                          ;C语言主程序入口
    IMPORT RunFirst
    IMPORT TargetResetInit                 ;目标板基本初始化
    IMPORT g_stay_iap

EXPORT __user_initial_stackheap

; Area Definition and Entry Point
; Startup Code must be linked first at Address at which it expects to run.
    CODE32
    PRESERVE8
                AREA    RESET, CODE, READONLY
                ARM

; Exception Vectors
; Mapped to Address 0.
; Absolute addressing mode must be used.
; Dummy Handlers are implemented as infinite loops which can be modified.

Vectors         LDR     PC, Reset_Addr
                LDR     PC, Undef_Addr
                LDR     PC, SWI_Addr
                LDR     PC, PAbt_Addr
                LDR     PC, DAbt_Addr
                NOP                            ; Reserved Vector
;               LDR     PC, IRQ_Addr
                LDR     PC, [PC, #-0x0120]     ; Vector from VicVectAddr
                LDR     PC, FIQ_Addr

Reset_Addr      DCD     Reset_Handler
Undef_Addr      DCD     Undef_Handler
SWI_Addr        DCD     SWI_Handler
PAbt_Addr       DCD     PAbt_Handler
DAbt_Addr       DCD     DAbt_Handler
                DCD     0                      ; Reserved Address
                DCD     0                      ; Reserved Address
FIQ_Addr        DCD     FIQ_Handler

Undef_Handler B Undef_Handler

SWI_Handler
        CMP     R0, #6
        LDRLO   PC, [PC, R0, LSL #2]
        MOVS    PC, LR

SwiFunction
        DCD     IRQDisable       ;0
        DCD     IRQEnable        ;1
        DCD     FIQDisable       ;2
        DCD     FIQEnable        ;3
        DCD     SoftReset        ;4
        DCD     PowerJump        ;5

IRQDisable
        ;关IRQ中断
        MRS     R0, SPSR
        ORR     R0, R0, #NoInt
        MSR     SPSR_c, R0
        MOVS    PC, LR

IRQEnable
        ;开IRQ中断
        MRS   R0, SPSR
        BIC   R0, R0, #NoInt
        MSR   SPSR_c, R0
        MOVS    PC, LR

FIQDisable
        ;关FIQ中断
        MRS     R0, SPSR
        ORR     R0, R0, #NoFIQ
        MSR     SPSR_c, R0
        MOVS    PC, LR

FIQEnable
        ;开FIQ中断
        MRS   R0, SPSR
        BIC   R0, R0, #NoFIQ
        MSR   SPSR_c, R0
        MOVS    PC, LR

SoftReset
;软件复位
B Vectors

PowerJump
;将CPU转换到特权模式后跳转
BX R1

PAbt_Handler    B       PAbt_Handler
DAbt_Handler    B       DAbt_Handler
FIQ_Handler     B       FIQ_Handler

; Reset Handler

EXPORT Reset_Handler
Reset_Handler

; 判断是否留在IAP中执行, 通过R0中的值来判断
        LDR     R1, =STAY_IN_IAP
        CMP     R0, R1
        LDR     R3, =g_stay_iap
        STREQ   R1, [R3] ; 为g_stay_iap赋值
        MOV     R1, #0
        STRNE R1, [R3]

        BL      RunFirst
        BL      InitStack               ; Initialize the stack 初始化堆
        BL      TargetResetInit         ; Initialize the target board 初始化目标板
                                        ; Jump to the entry point of C p
        B      __main
        B      _sys_exit

;: 初始化堆栈
InitStack
        MOV     R0, LR
;设置管理模式堆栈
        MSR     CPSR_c, #0xd3
        LDR     SP, StackSvc
;设置中断模式堆栈
        MSR     CPSR_c, #0xd2
        LDR     SP, StackIrq
;设置快速中断模式堆栈
        MSR     CPSR_c, #0xd1
        LDR     SP, StackFiq
;设置中止模式堆栈
        MSR     CPSR_c, #0xd7
        LDR     SP, StackAbt
;设置未定义模式堆栈
        MSR     CPSR_c, #0xdb
        LDR     SP, StackUnd
;设置系统模式堆栈
        MSR     CPSR_c, #0xd0
        LDR     SP, =StackUsr

BX R0

EXPORT _sys_exit
_sys_exit
B _sys_exit

;被0除
__rt_div0
MOV R0, #0
BX LR

;功能描述: 库函数初始化堆和栈，不能删除
__user_initial_stackheap
    LDR   R0, =bottom_of_heap
    LDR   R1, =StackUsr
    LDR   R2, =top_of_heap
    LDR   R3, =bottom_of_Stacks
    BX    LR

    LTORG
StackSvc           DCD     SvcStackSpace + (SVC_STACK_LEGTH)* 4
StackIrq           DCD     IrqStackSpace + (IRQ_STACK_LEGTH)* 4
StackFiq           DCD     FiqStackSpace + (FIQ_STACK_LEGTH)* 4
StackAbt           DCD     AbtStackSpace + (ABT_STACK_LEGTH)* 4
StackUnd           DCD     UndtStackSpace + (UND_STACK_LEGTH)* 4

;encrypt the chip
   IF . >= 0x1fc
        IF :DEF: EN_CRP
            INFO    1,"/nThe data at 0x000001fc must be 0x87654321./nPlease delete some source before this line."
        ELSE
            INFO    1,"/nThe data at 0x000001fc must be 0xffffffff./nPlease delete some source before this line."
        ENDIF
   ENDIF

CrpData
    WHILE . < 0x1fc
    NOP
    WEND

CrpData1
    IF :DEF: EN_CRP
    DCD     0x87654321          ;当此数为0x87654321时，用户程序被保护
    ELSE
    DCD     0xffffffff          ;当此数为0xffffffff时，用户程序不被保护
    ENDIF

;分配堆栈空间
        AREA    MyStacks, DATA, NOINIT, ALIGN=2
SvcStackSpace           SPACE   SVC_STACK_LEGTH * 4 ;管理模式堆栈空间
IrqStackSpace           SPACE   IRQ_STACK_LEGTH * 4 ;中断模式堆栈空间
FiqStackSpace           SPACE   FIQ_STACK_LEGTH * 4 ;快速中断模式堆栈空间
AbtStackSpace           SPACE   ABT_STACK_LEGTH * 4 ;中止义模式堆栈空间
UndtStackSpace          SPACE   UND_STACK_LEGTH * 4 ;未定义模式堆栈

        AREA    Heap, DATA, NOINIT
bottom_of_heap ;   SPACE   1
        AREA    HeapTop, DATA, NOINIT
top_of_heap

        AREA    StackBottom, DATA, NOINIT
bottom_of_Stacks ;    SPACE   1
        AREA    Stacks, DATA, NOINIT
StackUsr

END