三星cpu s3c2440 的中断向量表问题

以前一直搞不明明白，2440 的中断向量表为什么会是在 _ISR_STARTADDRESS=0x33FF_FF00？cpu是这么跳转到这个位置的？ 在零地址的终端向量表有做什么用。

今天有空，仔细研究了下，终于看清楚了。

 

 注意一下代码：

ENTRY;1)The code, which converts to Big-endian, should be in little endian code.;2)The following little endian code will be compiled in Big-Endian mode.; The code byte order should be changed as the memory bus width.;3)The pseudo instruction,DCD can't be used here because the linker generates error.ASSERT:DEF:ENDIAN_CHANGE[ ENDIAN_CHANGE ASSERT :DEF:ENTRY_BUS_WIDTH [ ENTRY_BUS_WIDTH=32bChangeBigEndian ;DCD 0xea000007 ] [ ENTRY_BUS_WIDTH=16andeqr14,r7,r0,lsl #20 ;DCD 0x0007ea00 ] [ ENTRY_BUS_WIDTH=8streqr0,[r0,-r10,ror #1] ;DCD 0x070000ea ]| bResetHandler ]bHandlerUndef;handler for Undefined modebHandlerSWI;handler for SWI interruptbHandlerPabort;handler for PAbortbHandlerDabort;handler for DAbortb.;reservedbHandlerIRQ;handler for IRQ interruptbHandlerFIQ;handler for FIQ interruptENTRY;1)The code, which converts to Big-endian, should be in little endian code.;2)The following little endian code will be compiled in Big-Endian mode.; The code byte order should be changed as the memory bus width.;3)The pseudo instruction,DCD can't be used here because the linker generates error.ASSERT:DEF:ENDIAN_CHANGE[ ENDIAN_CHANGE ASSERT :DEF:ENTRY_BUS_WIDTH [ ENTRY_BUS_WIDTH=32bChangeBigEndian ;DCD 0xea000007 ] [ ENTRY_BUS_WIDTH=16andeqr14,r7,r0,lsl #20 ;DCD 0x0007ea00 ] [ ENTRY_BUS_WIDTH=8streqr0,[r0,-r10,ror #1] ;DCD 0x070000ea ]| bResetHandler ]bHandlerUndef;handler for Undefined modebHandlerSWI;handler for SWI interruptbHandlerPabort;handler for PAbortbHandlerDabort;handler for DAbortb.;reservedbHandlerIRQ;handler for IRQ interruptbHandlerFIQ;handler for FIQ interrupt

 

以上代码就是中断向量，这个不用怀疑。

 

MACRO$HandlerLabel HANDLER $HandleLabel$HandlerLabelsubsp,sp,#4;decrement sp(to store jump address)stmfdsp!,{r0};PUSH the work register to stack(lr does't push because it return to original address)ldr r0,=$HandleLabel;load the address of HandleXXX to r0ldr r0,[r0] ;load the contents(service routine start address) of HandleXXXstr r0,[sp,#4] ;store the contents(ISR) of HandleXXX to stackldmfd sp!,{r0,pc} ;POP the work register and pc(jump to ISR)MEND

 

这个是宏定义

 

LTORGHandlerFIQ HANDLER HandleFIQHandlerIRQ HANDLER HandleIRQHandlerUndef HANDLER HandleUndefHandlerSWI HANDLER HandleSWIHandlerDabort HANDLER HandleDabortHandlerPabort HANDLER HandlePabort

 

中断向量函数， 注意：HandlerIRQ      HANDLER HandleIRQ 会根据上面的宏展开。

 

AREA RamData, DATA, READWRITE^ _ISR_STARTADDRESS; _ISR_STARTADDRESS=0x33FF_FF00HandleReset # 4HandleUndef # 4HandleSWI# 4HandlePabort # 4HandleDabort # 4HandleReserved # 4HandleIRQ# 4HandleFIQ# 4

 

定义在 0x33FF_FF00 位置的中断向量表。

 

基本上代码的流程是，每次中断到达后，还是执行 0 地址的中断向量表，中断向量调用HandlerIRQ    HANDLER HandleIRQ，HandlerIRQ      HANDLER HandleIRQ 展开后，实际执行 HandleIRQ  #   4。

 

另外需要注意的是，mmu 的设置 MMU_SetMTT(0x00000000,0x07f00000,(int)__ENTRY,RW_CNB);  保证 (int)__ENTRY 的位置永远在 0x00000000；