Execute program in absolute address

RE: Execute program in absolute address

chianglin — Sat, 10 Aug 2019 15:04:41 GMT

Hi,

Thank you

Chianglin

RE: Execute program in absolute address

RK — Fri, 09 Aug 2019 02:53:13 GMT

and why do you want to put a function at a specific address? It's a pretty unusual thing to want to do, in fact there's almost never a reason for it. You can do it with attributes on the function or a special linker map which forces the function into a section you define at one place and then you'd just call it and it would just work. However .. it really feels like you're trying to solve a different problem here.

You can google for how to put a function at a specific address, it depends on the compiler you're using. eg here's how Keil does it

RE: Execute program in absolute address

chianglin — Fri, 09 Aug 2019 02:20:23 GMT

Hi Hung Bui,

Sorry, the structure of bootloader is too complex for me.

Actually, I only want to do two jobs:

1. Put a function on the specified address (For example: put a function to address 0x10000).

2. Execute this function from other function. How can I execute this function my "Jump command" (For example: change "program counter" to 0x10000).

Would you please tell me how can I do these two job?

Thank you,

Chianglin

RE: Execute program in absolute address

Hung Bui — Thu, 08 Aug 2019 08:05:19 GMT

I'm not sure I understand what you want to do ?

Why do you want to locate your application at 0x1000 when leaving address 0x0000000 empty ? It won't work because the reset handler on Cortex M4 is hardcoded at 0x000000.

You need to have a program (or at least reset handler) at 0x000000 to jump to your application. That's why I suggested the bootloader.

RE: Execute program in absolute address

chianglin — Thu, 08 Aug 2019 07:19:03 GMT

Hi Hung Bui,

I had write a simple program which only blink a LED light, please find following attach file

devzone.nordicsemi.com/.../blinkyTest.7z

It can work correctly because the program is locate from 0x00000000, please find follwing image

If I locate program at 0x1000, the program will now work (Note: I had erase all the flash when I had erase all of the flash memory). please find following image.

Thank you,

Chianglin

RE: Execute program in absolute address

Hung Bui — Tue, 06 Aug 2019 11:17:15 GMT

Yes, you are right. By setting the iROM1 start address, the linker will generate the hex file with the absolute address to start at the address you configured.

If you want to make a program that run at 0x0000000 (I assume you don't use a softdevice) and switch to another program in different place in flash you are creating a bootloader.

We have a bootloader without softdevice example here.

It's from a very old post but the principle should be the same. You forward the vector table and then you jump the pc to the reset handler of the new application.