How can I inset a specific number into a executive code?

[Kim.Andy]

Posted on January 12, 2018 at 08:22

I have two executive files which there is a little difference between both files.

I want to distinguish two files by inserting a number in the specific place of the executive file.

Is it possible? If then, How can I do that?

[Bogdan Golab]

Posted on January 12, 2018 at 08:35

I guess it can be done in the startup file (*.s).

In Keil world:

http://www.keil.com/support/man/docs/armasm/armasm_dom1361290005934.htm

 

No sure what you want to achieve at the high level - maybe the problem can be solved different way.

[Bogdan Golab]

Posted on January 12, 2018 at 08:36

BTW. LPC processors have CRP marked this way in the memory at specific address:

                IF      :LNOT::DEF:NO_CRP

                AREA    |.ARM.__at_0x02FC|, CODE, READONLY                DCD     0xFFFFFFFF                ENDIF

[Tesla DeLorean]

Posted on January 12, 2018 at 12:55

I'd use one of the unused words in the front of the vector table. You could do this by editing the .S file or writing a small C application to modify the word in the .BIN file.

On the STM side use a pointer to access the word.

[Kim.Andy]

Posted on January 15, 2018 at 05:04

Hi, Clive..

How can I settle down this issue in the C level.

Could you give me an example?

Thanks

[Kim.Andy]

Posted on January 16, 2018 at 01:53

Hi Bogdan,

I insert your example code in my startup code like the following.

MODULE ?cstartup

;; Forward declaration of sections.

SECTION CSTACK:DATA:NOROOT(3)

SECTION .intvec:CODE:NOROOT(2)

EXTERN __iar_program_start

EXTERN SystemInit PUBLIC __vector_table

DATA

__vector_table DCD sfe(CSTACK) DCD Reset_Handler ; Reset Handler

DCD NMI_Handler ; NMI Handler

----------------------------------------------------------------

END

AREA |.ARM.__at_0x02FC|, CODE, READONLY

DCD 0xFFFFFFFF

But I can't find 0xfffffff at the 0x2FC, defined in the above AREA.

Please refer to the below binary file.

Could you let me know what is wrong?

Thanks, Bogdan.

[Tesla DeLorean]

Posted on January 16, 2018 at 02:45

Code past the END is going to be ignored.

From startup.s

...

DATA

__vector_table DCD sfe(CSTACK) DCD Reset_Handler ; Reset Handler DCD NMI_Handler ; NMI Handler DCD HardFault_Handler ; Hard Fault Handler DCD MemManage_Handler ; MPU Fault Handler DCD BusFault_Handler ; Bus Fault Handler DCD UsageFault_Handler ; Usage Fault Handler DCD 0 ; Reserved <--- this word at +0x1C DCD 0 ; Reserved +0x20 DCD 0 ; Reserved +0x24

...

From C

printf('%08X\n', *((uint32_t *)0x0800001C) );

[Tesla DeLorean]

Posted on January 16, 2018 at 02:56

>>

Could you let me know what is wrong?

Code past the END is going to be ignored

.

I would avoid AT directive, especially if code is otherwise placed in FLASH at 0x08000000 or 0x08010000

I attached some code, but that post is pending moderation

[Bogdan Golab]

Posted on January 16, 2018 at 07:23

My example was only to show how to use the assembler directive - 2FC location  is reserved by the NXP for LPC MCUs to protect (depending on the stored value) the content.