STMDB and LDMIA are not popping and pushing correctly hence my program
execution crashes at this instruction
.
I am using GCC 4.3.2 tools to make an elf file for an Arm9
"arm926ej-s"(at91sam9261) the example Disassemble is as listed below
<OSMutexAccept+0xb0>
4378: e5931000 ldr r1, [r3]
437c: e5d12036 ldrb r2, [r1, #54]
4380: e3cc30ff bic r3, ip, #255 ; 0xff
4384: e152042c cmp r2, ip, lsr #8
.
.This Code left for as its not neccessary
.
43b8: e8bd8070 pop {r4, r5, r6, pc}
43bc: ebfff066 bl 55c <OS_CPU_SR_Restore>
43c0: e5c56000 strb r6, [r5]
43c4: e3a00001 mov r0, #1 ; 0x1
43c8: e8bd8070 pop {r4, r5, r6, pc}
43cc: 000219e4 .word 0x000219e4
43d0: 000219e8 .word 0x000219e
When I debug the image on an ARM at91Sam The program loses control at
instruction 43c8(pop {r4, pc}, In the debugger this instruction is
dissassembled to:
LDMIA R13!, {R4, PC}
Which is a thumb instruction, how can i enforce that this is not used if
it is the source of my problems
could be a stack overflow. If you say execution crashes, what exception/interrupt vector is the processor going to?
Thank you for the reply. The program does not point to an interrupt. its actually the PC that runs wild after loading from an address with no valid instruction, I have since found out more, and need help to fix the problem with the stack pointer and memory/RAM that is addressable. If i move the stack pointer to a lower address than 00027A00 the program executes fine for a while until reset and SP goes back to that address range. The STMDB/STMFD instruction is unable to write to the address that the SP will be pointing to, then on the POP instruction the "2A2A2A2A" is loaded as PC I arm trying to run the uC-OS II that I have compiled on this board, . I have made a simple startup file and linker script from the templates online, examples smaller size
Watch this topic
Disable multi-page viewPlease log in before posting. Registration is free and takes only a minute.
Existing account
Do you have a Google/GoogleMail account? No registration required!
Log in with Google account
Log in with Google account
No account? Register here.