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2440启动代码分析

發布時間：2023/12/10 编程问答 16 豆豆

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;GET和INCLUDE功能相同

;功能：引進一個被編譯過的文件。

??????? GET option.inc

??????? GET memcfg.inc

??????? GET 2440addr.inc

;EQU為程序中的常量、標號等定義一個等效的字符名稱

;定義SDRAM工作在Refresh模式，SDRAM有兩種刷新方式：autorefresh和selfrefresh，前者是在其使用過程當中每隔一段時間發出刷新指令，SDRAM刷新一行，self refresh是在省電模式時使用

BIT_SELFREFRESH EQU??? (1<<22)?

;系統的工作模式設定,共七種工作模式

USERMODE??? EQU ?????? 0x10

FIQMODE???? EQU ?????? 0x11

IRQMODE???? EQU ?????? 0x12

SVCMODE???? EQU ?????? 0x13

ABORTMODE?? EQU ?????? 0x17

UNDEFMODE?? EQU ?????? 0x1b

MODEMASK??? EQU ?????? 0x1f

NOINT?????? EQU ?????? 0xc0

;系統的堆棧空間設定

UserStack????? EQU???? (_STACK_BASEADDRESS-0x3800)??? ;0x33ff4800 ~

SVCStack?????? EQU???? (_STACK_BASEADDRESS-0x2800)??? ;0x33ff5800 ~

UndefStack???? EQU???? (_STACK_BASEADDRESS-0x2400)??? ;0x33ff5c00 ~

AbortStack???? EQU???? (_STACK_BASEADDRESS-0x2000)??? ;0x33ff6000 ~

IRQStack?????? EQU???? (_STACK_BASEADDRESS-0x1000)??? ;0x33ff7000 ~

FIQStack?????? EQU???? (_STACK_BASEADDRESS-0x0)?????? ;0x33ff8000 ~

;這一段是為了統一處理器工作狀態和軟件編譯方式（16位編譯環境使用tasm.exe編譯）

;arm有兩種工作狀態:32位，該狀態執行字對準的arm指令；16位，該狀態執行半字對準的Thumb指令

;不同的工作狀態，編譯器編譯方式也不同

??????? GBLL??? THUMBCODE??? ;定義一個全局變量

??????? [ {CONFIG} = 16????? ; CONFIG為ADS定義的內部變量

THUMBCODE SETL?{TRUE} ;SETA 指令用于設置局部或全局算術變量的值,SETL 指令用于設置局部或全局邏輯變量的值,SETS 指令用于設置局部或全局字符串變量的值

??????? ??? CODE32?????????? ;工作在arm狀態

?????????????? |

THUMBCODE SETL?{FALSE}?;[ | ] 是ARM匯編控制偽指令，就是 IF ELSE ENDIF，簡寫成 [ | ]

??? ]

?????????????? MACRO?????????? ;宏定義

??????? MOV_PC_LR

?????????????? [ THUMBCODE

??????? ??? bx lr

?????????????? |

??????? ??? mov pc,lr

?????????????? ]

??????? MEND

?????????????? MACRO

??????? MOVEQ_PC_LR

?????????????? [ THUMBCODE

??????? bxeq lr

?????????????? |

??????? ??? moveq pc,lr

?????????????? ]

??????? MEND

;這段程序用于把中斷服務程序的首地址裝載到pc中，有人稱之為“加載程序”。

;本初始化程序定義了一個數據區（在文件最后），存放相應中斷服務程序的首地址。每個字空間都有一個標號，以Handle***命名。

?????????????? MACRO

$HandlerLabel HANDLER $HandleLabel

$HandlerLabel

??????? sub???? sp,sp,#4?????? ;用來存儲PC地址

??????? stmfd?? sp!,{r0}?????? ;把將要使用的r0寄存器入棧

??????? ldr???? r0,=$HandleLabel;給寄存器r0賦值

??????? ldr???? r0,[r0] ;給寄存器r0賦值,將r0的地址放入r0

??????? str???? r0,[sp,#4]????? ;將對應的中斷函數首地址入棧

??????? ldmfd?? sp!,{r0,pc}???? ;彈出工作寄存器ro和PC,也就完成了到ISR的跳轉

??????? MEND

??????? IMPORT?|Image$$RO$$Limit|?; 表示RO區末地址后面的地址，即RW數據源的起始地址

??????? IMPORT?|Image$$RW$$Base|?? ; RW區在RAM里的執行區起始地址，也就是編譯器選項RW_Base指定的地址。

??????? IMPORT?|Image$$ZI$$Base|?? ; ZI區在RAM里面的起始地址

??????? IMPORT?|Image$$ZI$$Limit|?; ZI區在RAM里面的結束地址后面的一個地址

??????? IMPORT?Main

??????? AREA??? Init,CODE,READONLY?;聲明一個代碼段

??????? ENTRY

??????? ;下面的代碼是小端和大端的轉換

?;條件編譯，在編譯成機器碼前就設定好

??????? ASSERT?:DEF:ENDIAN_CHANGE????????? ;判斷ENDIAN_CHANGE是否定義

??????? [ ENDIAN_CHANGE

??????? ??? ASSERT?:DEF:ENTRY_BUS_WIDTH??? ;如果已經定義了ENDIAN_CHANGE,判斷ENTRY_BUS_WIDTH是否定義

??????? ??? [ ENTRY_BUS_WIDTH=32??????????? ;判斷是不是為32

?????????????? b?????? ChangeBigEndian ??? ;DCD 0xea000007

??????? ??? ]

??????? ??? [ ENTRY_BUS_WIDTH=16

?????????????? andeq?? r14,r7,r0,lsl #20?? ;DCD 0x0007ea00

??????? ??? ]

??????? ??? [ ENTRY_BUS_WIDTH=8

?????????????? streq?? r0,[r0,-r10,ror #1] ;DCD 0x070000ea

??????? ??? ]

??????? |

??????? ??? b?? ResetHandler

??? ]

??????? b?????? HandlerUndef?? ;轉跳到Undefined mode程序入口

??????? b?????? HandlerSWI???? ;轉跳到SWI 中斷程序入口

??????? b?????? HandlerPabort?;轉跳到PAbort(指令異常)程序入口

??????? b?????? HandlerDabort?;轉跳到DAbort(數據異常)程序入口

??????? b?????? .????????????? ;保留

??????? b?????? HandlerIRQ???? ;轉跳到IRQ 中斷程序入口

??????? b?????? HandlerFIQ???? ;轉跳到FIQ 中斷程序入口

;@0x20

??????? b?????? EnterPWDN????? ; Must be @0x20.

??????? ;通過設置CP15的C1的位7，設置存儲格式為Bigendian，三種總線方式

ChangeBigEndian???? ;下面是改變大小端的程序,這里采用直接定義機器碼的方式

;@0x24

??????? [ ENTRY_BUS_WIDTH=32

??????? ??? DCD 0xee110f10???? ;0xee110f10 => mrc p15,0,r0,c1,c0,0

??????? ??? DCD 0xe3800080???? ;0xe3800080 => orr r0,r0,#0x80;?//Big-endian

??????? ??? DCD 0xee010f10???? ;0xee010f10 => mcr p15,0,r0,c1,c0,0

??????? ]

??????? [ ENTRY_BUS_WIDTH=16

??????? ??? DCD 0x0f10ee11

??????? ??? DCD 0x0080e380

??????? ??? DCD 0x0f10ee01

??????? ]

??????? [ ENTRY_BUS_WIDTH=8

??????? ??? DCD 0x100f11ee

??????? ??? DCD 0x800080e3

??????? ??? DCD 0x100f01ee

??? ]

??????? DCD 0xffffffff

??????? b ResetHandler

;掉電模式

;SDRAM自動刷新.

;進入PWDN

EnterPWDN

??????? mov r2,r0????????????? ;r2=rCLKCON

??????? tst r0,#0x8??????????? ;測試是否是SLEEP mode?

??????? bne ENTER_SLEEP

ENTER_STOP??????????? ;進入PWDN后如果不是sleep則進入stop

??????? ldr r0,=REFRESH

??????? ldr r3,[r0]??????????? ;r3=rREFRESH

??????? mov r1, r3

??????? orr r1, r1, #BIT_SELFREFRESH

??????? str r1, [r0]?????????? ;使SDRAM自動刷新

??????? mov r1,#16???????????????????? ;等待刷新，也可能不需要

0?????? subs r1,r1,#1

??????? bne %B0

??????? ldr r0,=CLKCON???????? ;進入STOP mode.

??????? str r2,[r0]

??????? mov r1,#32

0?????? subs r1,r1,#1

??????? bne %B0

?????????????????????? ; 進入SLEEP mode, 只有通過喚醒復位.

??????? ldr r0,=REFRESH ;退出SDRAM self refresh mode.

??????? str r3,[r0]

??????? MOV_PC_LR

ENTER_SLEEP

??????? ;rGSTATUS3有一個返回地址

??????? ldr r0,=REFRESH

??????? ldr r1,[r0]??????????? ;r1=rREFRESH

??????? orr r1, r1, #BIT_SELFREFRESH

??????? str r1, [r0]?????????? ;啟用SDRAM self-refresh

??????? mov r1,#16???????????????????? ;等待self-refresh,也可能不需要.

0?????? subs r1,r1,#1

??????? bne %B0

??????? ldr???? r1,=MISCCR

??????? ldr???? r0,[r1]

??????? orr???? r0,r0,#(7<<17)?;設置SCLK0=0, SCLK1=0, SCKE=0.

??????? str???? r0,[r1]

??????? ldr r0,=CLKCON???????? ;進入sleep mode

??????? str r2,[r0]

??????? b .??????????????????? ;CPU不工作.

WAKEUP_SLEEP

??????? ;Release SCLKn after wake-up from the SLEEP mode.

??????? ldr???? r1,=MISCCR

??????? ldr???? r0,[r1]

??????? bic???? r0,r0,#(7<<17)?;SCLK0:0->SCLK, SCLK1:0->SCLK, SCKE:0->=SCKE.

??????? str???? r0,[r1]

??????? ;設置存儲控制寄存器

??????? ldr???? r0,=SMRDATA

??????? ldr???? r1,=BWSCON???? ;總線寬度和等待控制寄存器

??????? add???? r2, r0, #52??? ;SMRDATA的結束地址

??????? ldr???? r3, [r0], #4

??????? str???? r3, [r1], #4

??????? cmp???? r2, r0

??????? bne???? %B0

?;數據在以SMRDATA為起始的存儲區

??????? mov r1,#256

0?????? subs r1,r1,#1?;1) wait until the SelfRefresh is released.

??????? bne %B0

??????? ldr r1,=GSTATUS3 ????? ;GSTATUS3 has the start address just after SLEEP wake-up

??????? ldr r0,[r1]

??????? mov pc,r0

;異常中斷宏調用

??????? LTORG

HandlerFIQ????? HANDLER HandleFIQ

HandlerIRQ????? HANDLER HandleIRQ

HandlerUndef??? HANDLER HandleUndef

HandlerSWI????? HANDLER HandleSWI

HandlerDabort?? HANDLER HandleDabort

HandlerPabort?? HANDLER HandlePabort

IsrIRQ

??????? sub???? sp,sp,#4?????? ;reserved for PC

??????? stmfd?? sp!,{r8-r9}

??????? ldr???? r9,=INTOFFSET

??????? ldr???? r9,[r9]

??????? ldr???? r8,=HandleEINT0

??????? add???? r8,r8,r9,lsl #2

??????? ldr???? r8,[r8]

??????? str???? r8,[sp,#8]

??????? ldmfd?? sp!,{r8-r9,pc}

;=======

; ENTRY

;板子上電和復位后,程序開始從位于0x00執行b ResetHandler,程序跳轉到這里執行

;=======

ResetHandler

??????? ldr???? r0,=WTCON?????? ;屏蔽看門狗

??????? ldr???? r1,=0x0

??????? str???? r1,[r0]

??????? ldr???? r0,=INTMSK

??????? ldr???? r1,=0xffffffff?;屏蔽所有的中斷

??????? str???? r1,[r0]

??????? ldr???? r0,=INTSUBMSK

??????? ldr???? r1,=0x3ff????????????? ;屏蔽所有的子中斷

??????? str???? r1,[r0]

??????? [ {FALSE}

??????? ; rGPFDAT = (rGPFDAT & ~(0xf<<4)) | ((~data & 0xf)<<4);

??????? ; Led_Display

??????? ldr???? r0,=GPFCON

??????? ldr???? r1,=0x5500

??????? str???? r1,[r0]

??????? ldr???? r0,=GPFDAT

??????? ldr???? r1,=0x10

??????? str???? r1,[r0]

??????? ]

??????? ;根據工作頻率設置pll

??????? ldr???? r0,=LOCKTIME

??????? ldr???? r1,=0xffffff

??????? str???? r1,[r0]

??? [ PLL_ON_START

??????? ; 為2440添加時鐘設備.

??????? ; 設置Fclk:Hclk:Pclk

??????? ldr???? r0,=CLKDIVN

??????? ldr???? r1,=CLKDIV_VAL???????? ; 0=1:1:1, 1=1:1:2, 2=1:2:2, 3=1:2:4, 4=1:4:4, 5=1:4:8, 6=1:3:3, 7=1:3:6.

??????? str???? r1,[r0]

??????? ;Configure UPLL

??????? ldr???? r0,=UPLLCON

??????? ldr???? r1,=((U_MDIV<<12)+(U_PDIV<<4)+U_SDIV)?;設定系統主時鐘頻率

??????? str???? r1,[r0]

??????? nop???? ; Caution: After UPLL setting, at least 7-clocks delay must be inserted for setting hardware be completed.

??????? nop

??????? ;配置MPLL

??????? ldr???? r0,=MPLLCON

??????? ldr???? r1,=((M_MDIV<<12)+(M_PDIV<<4)+M_SDIV)

??????? str???? r1,[r0]

??? ]

?;檢查啟動是從休眠模式喚醒.

??????? ldr???? r1,=GSTATUS2

??????? ldr???? r0,[r1]

??????? tst???? r0,#0x2

??????? ;是從休眠模式喚醒,跳轉到SLEEP_WAKEUP handler.

??????? bne???? WAKEUP_SLEEP

??????? EXPORT StartPointAfterSleepWakeUp

StartPointAfterSleepWakeUp

??????? ;設置存儲相關寄存器的程序

?;SMRDATA中涉及的值請參考memcfg.inc程序

??????? ldr???? r0,=SMRDATA

??????? ldr???? r1,=BWSCON???? ;BWSCON地址

??????? add???? r2, r0, #52??? ;SMRDATA結束地址

??????? ldr???? r3, [r0], #4

??????? str???? r3, [r1], #4

??????? cmp???? r2, r0

??????? bne???? %B0

?????????????? ;初始化堆棧

??????? bl????? InitStacks

?????? ; 設置缺省中斷處理函數

??????? ldr???? r0,=HandleIRQ?????? ;This routine is needed

??????? ldr???? r1,=IsrIRQ???? ?;if there isn't 'subs pc,lr,#4' at 0x18, 0x1c

??????? str???? r1,[r0]

;將數據段拷貝到RAM中,將ZI數據段清零,跳入C語言的main函數執行。

??????? ;If main() is used, the variable initialization will be done in __main().

??? [?? :LNOT:USE_MAIN

??? ??? ;Copy and paste RW data/zero initialized data

??????? LDR???? r0, =|Image$$RO$$Limit| ; Get pointer to ROM data

??????? LDR???? r1, =|Image$$RW$$Base|?; and RAM copy

??????? LDR???? r3, =|Image$$ZI$$Base|?

??????? ;Zero init base => top of initialised data

??????? CMP???? r0, r1????? ; Check that they are different

??????? BEQ???? %F2

??????? CMP???? r1, r3????? ; Copy init data

??????? LDRCC?? r2, [r0], #4??? ;--> LDRCC r2, [r0] + ADD r0, r0, #4

??????? STRCC?? r2, [r1], #4??? ;--> STRCC r2, [r1] + ADD r1, r1, #4

??????? BCC???? %B1

??????? LDR???? r1, =|Image$$ZI$$Limit| ; Top of zero init segment

??????? MOV???? r2, #0

??????? CMP???? r3, r1????? ; Zero init

??????? STRCC?? r2, [r3], #4

??????? BCC???? %B3

??? ]

??? [ :LNOT:THUMBCODE

??? ??? bl????? Main??????? ;Don't use main() because ......

??? ??? b?????? .

??? ]

??? [ THUMBCODE???????? ;for start-up code for Thumb mode

??? ??? orr???? lr,pc,#1

??? ??? bx????? lr

??? ??? CODE16

??? ??? bl????? Main??????? ;Don't use main() because ......

??? ??? b?????? .

??? ??? CODE32

??? ]

;初始化各模式下的堆棧指針

InitStacks

??????? ;Don't use DRAM,such as stmfd,ldmfd......

??????? ;SVCstack is initialized before

??????? ;Under toolkit ver 2.5, 'msr cpsr,r1' can be used instead of 'msr cpsr_cxsf,r1'

??????? mrs???? r0,cpsr

??????? bic???? r0,r0,#MODEMASK

??????? orr???? r1,r0,#UNDEFMODE|NOINT

??????? msr???? cpsr_cxsf,r1?????????? ;UndefMode

??????? ldr???? sp,=UndefStack???????? ; UndefStack=0x33FF_5C00

??????? orr???? r1,r0,#ABORTMODE|NOINT

??????? msr???? cpsr_cxsf,r1?????????? ;AbortMode

??????? ldr???? sp,=AbortStack???????? ; AbortStack=0x33FF_6000

??????? orr???? r1,r0,#IRQMODE|NOINT

??????? msr???? cpsr_cxsf,r1?????????? ;IRQMode

??????? ldr???? sp,=IRQStack?????????? ; IRQStack=0x33FF_7000

??????? orr???? r1,r0,#FIQMODE|NOINT

??????? msr???? cpsr_cxsf,r1?????????? ;FIQMode

??????? ldr???? sp,=FIQStack?????????? ; FIQStack=0x33FF_8000

??????? bic???? r0,r0,#MODEMASK|NOINT

??????? orr???? r1,r0,#SVCMODE

??????? msr???? cpsr_cxsf,r1?????????? ;SVCMode

??????? ldr???? sp,=SVCStack?????????? ; SVCStack=0x33FF_5800

??????? ;USER mode has not be initialized.

??????? mov???? pc,lr

??????? ;The LR register won't be valid if the current mode is not SVC mode.

;=====================================================================

; 時鐘測試

; Assemble code, because VSYNC time is very short

;=====================================================================

??????? EXPORT CLKDIV124

??????? EXPORT CLKDIV144

CLKDIV124

??????? ldr???? r0, = CLKDIVN

??????? ldr???? r1, = 0x3????????????? ; 0x3 = 1:2:4

??????? str???? r1, [r0]

;延時時鐘穩定

??????? nop

??????? ldr???? r0, = REFRESH

??????? ldr???? r1, [r0]

??????? bic??????????? r1, r1, #0xff

??????? bic??????????? r1, r1, #(0x7<<8)

??????? orr??????????? r1, r1, #0x470 ; REFCNT135

??????? str???? r1, [r0]

??????? nop

??????? mov???? pc, lr

CLKDIV144

??????? ldr???? r0, = CLKDIVN

??????? ldr???? r1, = 0x4????????????? ; 0x4 = 1:4:4

??????? str???? r1, [r0]

;延時時鐘穩定

??????? nop

??????? ldr???? r0, = REFRESH

??????? ldr???? r1, [r0]

??????? bic??????????? r1, r1, #0xff

??????? bic??????????? r1, r1, #(0x7<<8)

??????? orr??????????? r1, r1, #0x630 ; REFCNT675 - 1520

??????? str???? r1, [r0]

??????? nop

??????? mov???? pc, lr

??????? LTORG

SMRDATA DATA

;存儲器控制寄存器的定義區

; 存儲器訪問周期參數

; The memory settings is?safe parameters even at HCLK=75Mhz.

; SDRAM refresh period is for HCLK<=75Mhz.

??????? DCD (0+(B1_BWSCON<<4)+(B2_BWSCON<<8)+(B3_BWSCON<<12)+(B4_BWSCON<<16)+(B5_BWSCON<<20)+(B6_BWSCON<<24)+(B7_BWSCON<<28))

??????? DCD ((B0_Tacs<<13)+(B0_Tcos<<11)+(B0_Tacc<<8)+(B0_Tcoh<<6)+(B0_Tah<<4)+(B0_Tacp<<2)+(B0_PMC))?? ;GCS0

??????? DCD ((B1_Tacs<<13)+(B1_Tcos<<11)+(B1_Tacc<<8)+(B1_Tcoh<<6)+(B1_Tah<<4)+(B1_Tacp<<2)+(B1_PMC))?? ;GCS1

??????? DCD ((B2_Tacs<<13)+(B2_Tcos<<11)+(B2_Tacc<<8)+(B2_Tcoh<<6)+(B2_Tah<<4)+(B2_Tacp<<2)+(B2_PMC))?? ;GCS2

??????? DCD ((B3_Tacs<<13)+(B3_Tcos<<11)+(B3_Tacc<<8)+(B3_Tcoh<<6)+(B3_Tah<<4)+(B3_Tacp<<2)+(B3_PMC))?? ;GCS3

??????? DCD ((B4_Tacs<<13)+(B4_Tcos<<11)+(B4_Tacc<<8)+(B4_Tcoh<<6)+(B4_Tah<<4)+(B4_Tacp<<2)+(B4_PMC))?? ;GCS4

??????? DCD ((B5_Tacs<<13)+(B5_Tcos<<11)+(B5_Tacc<<8)+(B5_Tcoh<<6)+(B5_Tah<<4)+(B5_Tacp<<2)+(B5_PMC))?? ;GCS5

??????? DCD ((B6_MT<<15)+(B6_Trcd<<2)+(B6_SCAN))??? ;GCS6

??????? DCD ((B7_MT<<15)+(B7_Trcd<<2)+(B7_SCAN))??? ;GCS7

??????? DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Trc<<18)+(Tchr<<16)+REFCNT)

??????? DCD 0x32?????? ??? ;SCLK power saving mode, BANKSIZE 128M/128M

??????? DCD 0x30?????? ??? ;MRSR6 CL=3clk

??????? DCD 0x30?????? ??? ;MRSR7 CL=3clk

??????? ALIGN

??????? AREA RamData, DATA, READWRITE

??????? ^?? _ISR_STARTADDRESS????????? ; _ISR_STARTADDRESS=0x33FF_FF00

HandleReset ?? #?? 4

HandleUndef ?? #?? 4

HandleSWI????????????? #?? 4

HandlePabort??? #?? 4

HandleDabort??? #?? 4

HandleReserved?#?? 4

HandleIRQ????????????? #?? 4

HandleFIQ????????????? #?? 4

;不要使用標簽'IntVectorTable',

;The value of IntVectorTable is different with the address you think it may be.

;IntVectorTable

;@0x33FF_FF20

HandleEINT0??????????? #?? 4

HandleEINT1??????????? #?? 4

HandleEINT2??????????? #??4

HandleEINT3??????????? #?? 4

HandleEINT4_7?#?? 4

HandleEINT8_23 #?? 4

HandleCAM????????????? #?? 4????????? ; Added for 2440.

HandleBATFLT?? #?? 4

HandleTICK???????????? #?? 4

HandleWDT????????????? #?? 4

HandleTIMER0 ?#?? 4

HandleTIMER1 ?#?? 4

HandleTIMER2 ?#?? 4

HandleTIMER3 ?#?? 4

HandleTIMER4 ?#?? 4

HandleUART2??#?? 4

;@0x33FF_FF60

HandleLCD ???????????? #?? 4

HandleDMA0???????????? #?? 4

HandleDMA1???????????? #?? 4

HandleDMA2???????????? #?? 4

HandleDMA3???????????? #?? 4

HandleMMC????????????? #?? 4

HandleSPI0???????????? #?? 4

HandleUART1??????????? #?? 4

HandleNFCON??????????? #?? 4????????? ; Added for 2440.

HandleUSBD???????????? #?? 4

HandleUSBH???????????? #?? 4

HandleIIC????????????? #?? 4

HandleUART0 ?? #?? 4

HandleSPI1 ??????????? #?? 4

HandleRTC ???????????? #?? 4

HandleADC ???????????? #?? 4

;@0x33FF_FFA0

??? END

轉載于:https://www.cnblogs.com/b2tang/archive/2009/12/23/1630360.html

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