S3C2440启动代码 中断分析
1.建立中断向量表
b ResetHandler;hereis the first instrument 0x00这是第一条执行的指令
b HandlerUndef ;handler for Undefined mode
b HandlerSWI ;handler for SWI interrupt
b HandlerPabort ;handler for PAbort
b HandlerDabort ;handler for DAbort
b . ;reserved
b HandlerIRQ ;handler for IRQ interrupt
b HandlerFIQ ;handler for FIQ interrupt
2. 设置缺省中断处理函数
;将普通中断判断程序的入口地址给HandleIRQ
ldr r0,=HandleIRQ ;This routine is needed
ldr r1,=IsrIRQ ;ifthere isnt subs pc,lr,#4 at 0x18, 0x1c
str r1,[r0]
3.IRQ的中断服务程序
IsrIRQ
sub sp,sp,#4;reserved for PC
stmfd sp!,{r8-r9}
ldr r9,=INTOFFSET ;地址为0x4a000014的空间存着中断的偏移
ldr r9,[r9]
ldr r8,=HandleEINT0
add r8,r8,r9,lsl#2
ldr r8,[r8]
str r8,[sp,#8]
ldmfd sp!,{r8-r9,pc}
;外部中断号判断,通过中断服务程序入口地址存储器的地址偏移确定
;PC=[HandleEINT0+[INTOFFSET]]
4.中断处理
HandlerFIQ HANDLER HandleFIQ
HandlerIRQ HANDLER HandleIRQ
HandlerUndef HANDLER HandleUndef
HandlerSWI HANDLER HandleSWI
HandlerDabort HANDLER HandleDabort
HandlerPabort HANDLER HandlePabort
5.将$HandleLabel地址空间中的数据给PC
MACRO
$HandlerLabel HANDLER $HandleLabel
$HandlerLabel
sub sp,sp,#4 ;decrementsp(to store jump address) sp=sp-4
stmfd sp!,{r0} ;PUSH the work register to stack(lr doest push because it return to originaladdress) r0进栈
ldr r0,=$HandleLabel;load the address ofHandleXXX to r0
ldr r0,[r0] ;load the contents(service routine start address) of HandleXXX
str r0,[sp,#4] ;store the contents(ISR) of HandleXXX tostack r0进栈,将ro中的数据写入sp+4为地址的存储器中
ldmfd sp!,{r0,pc} ;POP the work register and pc(jump to ISR) 恢复r0的值,同时也将$HandleLabel地址空间中的数据给PC
MEND
;将$HandleLabel地址空间中的数据给PC,中断服务程序的入口
6 中断向量表
ALIGN
AREARamData, DATA, READWRITE
^ _ISR_STARTADDRESS ; _ISR_STARTADDRESS=0x33FF_FF00
;表定位在 RAM 高端,基地址为 _ISR_STARTADDRESS
;^是MAP的同义词,#是FIELD的同义词
HandleReset # 4
HandleUndef # 4
HandleSWI # 4
HandlePabort # 4
HandleDabort # 4
HandleReserved # 4
HandleIRQ # 4
HandleFIQ # 4
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
7映射(定义一个指针的指针)
/ Exception vector
#define pISR_RESET (*(unsigned *)(_ISR_STARTADDRESS+0x0))
#define pISR_UNDEF (*(unsigned *)(_ISR_STARTADDRESS+0x4))
#define pISR_SWI (*(unsigned *)(_ISR_STARTADDRESS+0x8))
#define pISR_PABORT (*(unsigned *)(_ISR_STARTADDRESS+0xc))
#define pISR_DABORT (*(unsigned *)(_ISR_STARTADDRESS+0x10))
#define pISR_RESERVED (*(unsigned *)(_ISR_STARTADDRESS+0x14))
#define pISR_IRQ (*(unsigned *)(_ISR_STARTADDRESS+0x18))
#define pISR_FIQ (*(unsigned *)(_ISR_STARTADDRESS+0x1c))
// Interrupt vector
#define pISR_EINT0 (*(unsigned *)(_ISR_STARTADDRESS+0x20))
#define pISR_EINT1 (*(unsigned *)(_ISR_STARTADDRESS+0x24))
#define pISR_EINT2 (*(unsigned *)(_ISR_STARTADDRESS+0x28))
#define pISR_EINT3 (*(unsigned *)(_ISR_STARTADDRESS+0x2c))
#define pISR_EINT4_7 (*(unsigned *)(_ISR_STARTADDRESS+0x30))
#define pISR_EINT8_23 (*(unsigned *)(_ISR_STARTADDRESS+0x34))
#define pISR_CAM (*(unsigned *)(_ISR_STARTADDRESS+0x38)) // Added for 2440.
#define pISR_BAT_FLT (*(unsigned *)(_ISR_STARTADDRESS+0x3c))
#define pISR_TICK (*(unsigned *)(_ISR_STARTADDRESS+0x40))
#define pISR_WDT_AC97 (*(unsigned*)(_ISR_START
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