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            S3C2410中斷詳解

            作者: 時間:2016-11-11 來源:網(wǎng)絡(luò) 收藏
            最開始的代碼,大家都很熟悉,最基本的中斷跳轉(zhuǎn)

            bResetHandler

            本文引用地址:http://www.biyoush.com/article/201611/316988.htm

            bHandlerUndef;handler for Undefined mode
            bHandlerSWI;handler for SWI interrupt
            bHandlerPabort;handler for PAbort
            bHandlerDabort;handler for DAbort
            b.;reserved
            bHandlerIRQ;handler for IRQ interrupt
            bHandlerFIQ;handler for FIQ interrupt

            跳轉(zhuǎn)的標(biāo)號是一系列的宏

            LTORG
            HandlerFIQ HANDLER HandleFIQ
            HandlerIRQ HANDLER HandleIRQ
            HandlerUndef HANDLER HandleUndef
            HandlerSWI HANDLER HandleSWI
            HandlerDabort HANDLER HandleDabort
            HandlerPabort HANDLER HandlePabort

            該宏在文件的最前面實現(xiàn),做了一些跳轉(zhuǎn)前的處理。如下:

            MACRO
            $HandlerLabel HANDLER $HandleLabel

            $HandlerLabel
            subsp,sp,#4 ;decrement sp(to store jump address)
            stmfdsp!,{r0} ;PUSH the work register to stack(lr doest push because it return to original address)
            ldr r0,=$HandleLabel;load the address of HandleXXX to r0
            ldr r0,[r0] ;load the contents(service routine start address) of HandleXXX
            str r0,[sp,#4] ;store the contents(ISR) of HandleXXX to stack
            ldmfd sp!,{r0,pc} ;POP the work register and pc(jump to ISR)
            MEND

            以HandleIRQ跳轉(zhuǎn)為例說明中斷的二級跳轉(zhuǎn)流程,以上的宏代碼說明IRQ跳轉(zhuǎn)到了標(biāo)號HandleIRQ處,該標(biāo)號如下定義:(是一系列的中斷以及二級中斷入口地址)

            AREA RamData, DATA, READWRITE

            ^ _ISR_STARTADDRESS ;(該值自己定義,是存放中斷向量表的地址)
            HandleReset # 4
            HandleUndef # 4
            HandleSWI # 4
            HandlePabort # 4
            HandleDabort # 4
            HandleReserved # 4
            HandleIRQ # 4
            HandleFIQ # 4

            ;Dont use the label IntVectorTable,
            ;The value of IntVectorTable is different with the address you think it may be.
            ;IntVectorTable(二級IRQ中斷向量表)
            HandleEINT0 # 4
            HandleEINT1 # 4
            HandleEINT2 # 4
            HandleEINT3 # 4
            HandleEINT4_7# 4
            HandleEINT8_23# 4
            HandleRSV6# 4
            HandleBATFLT # 4
            HandleTICK # 4
            HandleWDT# 4
            HandleTIMER0 # 4
            HandleTIMER1 # 4
            HandleTIMER2 # 4
            HandleTIMER3 # 4
            HandleTIMER4 # 4
            HandleUART2 # 4
            HandleLCD # 4
            HandleDMA0# 4
            HandleDMA1# 4
            HandleDMA2# 4
            HandleDMA3# 4
            HandleMMC# 4
            HandleSPI0# 4
            HandleUART1# 4
            HandleRSV24# 4
            HandleUSBD# 4
            HandleUSBH# 4
            HandleIIC # 4
            HandleUART0 # 4
            HandleSPI1 # 4
            HandleRTC # 4
            HandleADC # 4

            而HandleIRQ由以下代碼賦值,可以看出跳轉(zhuǎn)到了IsrIRQ:

            drr0,=HandleIRQ ;This routine is needed
            ldrr1,=IsrIRQ ;if there isnt subs pc,lr,#4 at 0x18, 0x1c放置中斷跳轉(zhuǎn)
            strr1,[r0]

            IsrIRQ ;真正的IRQ中斷的入口
            subsp,sp,#4 ;reserved for PC留出一個位置保存中斷入口地址
            stmfdsp!,{r8-r9}

            ldrr9,=INTOFFSET
            ldrr9,[r9] ;讀入中斷偏移碼
            ldrr8,=HandleEINT0 ;二級跳轉(zhuǎn)表的首地址
            addr8,r8,r9,lsl #2 ;R8=R8+R9X4得到相應(yīng)的中斷入口地址
            ldrr8,[r8]
            strr8,[sp,#8] ;中斷入口地址送進SP(第一個代碼留出的4字節(jié)空間)
            ldmfdsp!,{r8-r9,pc}

            到此為止,中斷已經(jīng)順利的進入了中斷向量表,用C語言編寫服務(wù)程序已變的非常簡單。如EINT0中斷的ISR

            void Eint0(void)

            { }

            pISR_EINT0=(U32)Eint0; //用中斷入口指向函數(shù)指針即可。



            關(guān)鍵詞: S3C2410中斷詳

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