Stuck at Startup code

report using the proper tags.

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     0
PAbt_Addr       DCD     PAbt_Handler
DAbt_Addr       DCD     DAbt_Handler
                DCD             0            ; Reserved Address
IRQ_Addr
                                 DCD     0
FIQ_Addr        DCD     FIQ_Handler


Undef_Handler   B       Undef_Handler
SWI_Handler     B       SWI_Handler
PAbt_Handler    B       PAbt_Handler
DAbt_Handler    B       DAbt_Handler
;IRQ_Handler     B       IRQ_Handler
FIQ_Handler     B       FIQ_Handler

; Reset Handler

                EXPORT  Reset_Handler
Reset_Handler

; Setup Stack for each mode
                LDR     R0, =Stack_Top

;  Enter Undefined Instruction Mode and set its Stack Pointer
                MSR     CPSR_c, #Mode_UND:OR:I_Bit:OR:F_Bit
                MOV     SP, R0
                SUB     R0, R0, #UND_Stack_Size

;  Enter Abort Mode and set its Stack Pointer
                MSR     CPSR_c, #Mode_ABT:OR:I_Bit:OR:F_Bit
                MOV     SP, R0
                SUB     R0, R0, #ABT_Stack_Size

;  Enter FIQ Mode and set its Stack Pointer
                MSR     CPSR_c, #Mode_FIQ:OR:I_Bit:OR:F_Bit
                MOV     SP, R0
                SUB     R0, R0, #FIQ_Stack_Size

;  Enter IRQ Mode and set its Stack Pointer
                MSR     CPSR_c, #Mode_IRQ:OR:I_Bit:OR:F_Bit
                MOV     SP, R0
                SUB     R0, R0, #IRQ_Stack_Size

;  Enter Supervisor Mode and set its Stack Pointer
                MSR     CPSR_c, #Mode_SVC:OR:I_Bit:OR:F_Bit
                MOV     SP, R0
                SUB     R0, R0, #SVC_Stack_Size

;  Enter User Mode and set its Stack Pointer
                MSR     CPSR_c, #Mode_USR
                MOV     SP, R0
                SUB     SL, SP, #USR_Stack_Size

                        ;       IMPORT  TargetResetInit
                        ;       BL              TargetResetInit

; Enter the C code

                IMPORT  __main
                LDR     R0, =__main
                BX      R0


; User Initial Stack & Heap
                AREA    |.text|, CODE, READONLY

                IMPORT  __use_two_region_memory
                EXPORT  __user_initial_stackheap
__user_initial_stackheap

                LDR     R0, =  Heap_Mem
                LDR     R1, =(Stack_Mem + USR_Stack_Size)
                LDR     R2, = (Heap_Mem +      Heap_Size)
                LDR     R3, = Stack_Mem
                BX      LR

                END

While debugging the execution stuck at "BX R0"
and instead of jump to main,program execution enter to below loop.

0x0000012C E2522010 SUBS R2,R2,#0x00000010
0x00000130 28A10078 STMCSIA R1!,{R3-R6}
0x00000134 8AFFFFFC BHI 0x0000012C

What will be the problem.
Plz give some suggestions or solution to this problem

While debugging the execution stuck at "BX R0"

I can't seem to find "BX R0" in the code you posted.

I can't seem to find "BX R0" in the code you posted.

Oh, there it is. Sorry, must have made a mistake using the search function.

While debugging the execution stuck at "BX R0"
and instead of jump to main,program execution enter to below loop.
...
What will be the problem.

Why do you think there is a problem? Did you expected that the instruction "BX R0" would jump to main()? Actually, this instruction jumps into standard library initialization code which initializes static variables, stack and heap, and then jumps to main(). The loop you are referring to is zeroing code: uninitialized static variables are filled with zeros prior to main().
If program flow doesn't reach main() eventually, then you have a problem...

Just out of curiosity, what does main() look like?

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

Please check the red marked codes, you should have 8 exception vectors, but looks like you have 9.

If it is not reaching main() what might be the problem

In our case it is going back to begining of startup code

While debugging the execution restart from start up at

0x00005458 DFAB SWI 0xAB

What will be the reason?

Thank you

http://www.keil.com/forum/docs/thread7666.asp

Did you read John Linqs post? There should only be 8 interrupt vectors, not 9.

Right now, you seem to have to handlers for the normal IRQ. One with a hard-coded handler, and one using the Vic vector lookup.

Remove the line with the IRQ_Addr handler, or change it to:

;               LDR     PC, IRQ_Addr