sysbios linker .cmd

Are you using TI or GCC tools?

Which target, platform, and device are you building for?

Which version of SYS/BIOS and XDCTOOLS are you using?

Alan

TI CCS

Code Composer Studio Version: 5.2.1.00018

 SYS/BIOS:  6.33.04.46

xdc tool: 3.23.03.53

Regards,

Lusheng

Hi Lusheng,

The following link would help you to understand the basics of memory management and section arrangement.

http://rtsc.eclipse.org/docs-tip/Memory_Management

Regards,
Kawada 

Hi Quote,

I also want to add one linker cmd such as am335x.cmd.

Can you give me one guide to write linker cmd? 

Regards,

Lusheng

Hi Lusheng,

Xdc will automatically create .cmd file by referring the "platform" you are selecting in RTSC configuration.
So, the basic memory definitions and section arrangements have been done automatically.
If you want to modify the section arrangement, you can override that by modifying your .cfg file as I informed you before. 

Now, if you want to add/modify the linker settings by .cmd file, you can still do that by adding your own .cmd file to your project such as am335x.cmd.
Please note the memories defined in MEMORY directive in your .cmd file may be already defined in the "platform". In this case, the errors will be raised during linking time.
If you want to change the definitions of memories, you can create your own platform :

http://rtsc.eclipse.org/docs-tip/Demo_of_the_RTSC_Platform_Wizard_in_CCSv4

Or, just remove MEMORY directive from your cmd file not to duplicate the definitions of memories and to rely on the memories generated by "platform".

Regards,
Kawada 

Another question: 

How is .bss(initialized) cleared when booting? 

If .data or .rodata is not continuous, who will move the sections from load address to running address?

Can you tell me the sequence fo section initialization in sysbios?

As for the section initialization, I think there is no difference between bios system and non-bios system.
c_int00 from run time support library will setup the required C runtime environment and section initializations will be done at this time. In addition to this, if using bios system, some setup routine will run at this time.

Now, your comment "How is .bss(initialized) cleared when booting" was not clear for me.

Basically, the .bss initialization will be done in c_int00, but only done having the initial value. For example, please take a look the following:

Int g_data1 = 1; // This global variable will be initialized with 1 before main().

Int g_data2; // This global variable will NOT be initialized with zero before main().

I'm not sure about AM335x runtime, but this is my understanding about Ti's runtime.
Please verify that your global variable not having the initial value is not being initialized with 0 when PC is coming to main().

Is this answer your question ?

Regards,
Kawada 

In load.cmd, .bss is last, but in final map, .bss(when .bss size is larger than text) is  in between boot code and .text. It will add the size of load image.

You know, I want to place .bss into the last so that the final image can be small. 

How can I put bss in the end of image whatever is the size of .bbs?

In spec  ARMAssemblyLanguageToolsv5.1

ReducingMemoryFragmentation: 

Eachoutputsectionthat is included in aspecific,namedmemoryrange orthat hasmemoryattribute
restrictionsis allocated.Eachoutputsectionis placedinto the first availablespacewithinthe named
area,consideringalignmentwherenecessary.

Anyremaining sectionsareallocatedin the orderin whichthey aredefined.Sectionsnotdefinedin a
SECTIONSdirectiveareallocatedin the orderin whichthey areencountered.Eachoutputsectionis
placedinto the first availablememoryspace,consideringalignmentwherenecessary.