Stack placement for task in SYS BIOS 6

palanivel guruvareddiar

Prodigy 100 points

Other Parts Discussed in Thread: SYSBIOS

Hi,

I'm in the process of implementing an application in SYS BIOS 6_30_02_42 in OMAP L138.

void myfunc()

{

Thread A creation;

.......

}

int main()

{

/* Some code */

BIOS_start(); // Entry point for BIOS is set to myfunc in the .cfg file

}

If I place the stack for Thread A in default heap, application works fine.

Now, I created one more heap and hook it in to the DDR in the .cfg as follows,

var extstackParams = new HeapMem.Params();
extstackParams.size = 0x040000;
extstackParams.sectionName = "EXTMEM_STACK_HEAP";
Program.global.sdramstack = HeapMem.create(extstackParams);
Program.sectMap["EXTMEM_STACK_HEAP"] = "DDR";

and in my application file app.c I did the following,

extern int EXTMEM_STACK_HEAP

mytask.stackHeap = (xdc_runtime_IHeap_Handle) EXTMEM_STACK_HEAP;

But when I'm trying to link, the linker shows the following error,

undefined
symbol
---------
_EXTMEM_STACK_HEAP

If I look in to the map file, the EXTMEM_STACK_HEAP is created as a section.

How to acheive this?

Thanks In advance

Regards

Palanivel

over 14 years ago

0 ToddMullanix over 14 years ago

TI__Guru* 96960 points

Hi Palanivel,

Try the following in the .c file. This is the heap you created. Note: you do not need to extern it if you have "#include <xdc/cfg/global.h>"

mytask.stackHeap = sdramstack;

Note: I'm assuming mytask is a Task_Params struct that is passed into Task_create.

Todd

0 Chris McCormick over 14 years ago

TI__Expert 4095 points

You need to pass an actual heap handle to the 'stackHeap' parameter, and not just the name of a section.

In your config script, the line:

Program.global.sdramstack = HeapMem.create(extstackParams);

Creates a HeapMem handle and assigns it to the global symbol 'sdramstack'. It's this handle that you want to assign to 'stackHeap'. Make sure to #include <xdc/cfg/global.h>, and you should be able to reference the symbol 'sdramstack'.

Also, to be technically correct, there is a macro defined for casting the HeapMem handle to an IHeap. So, your C code should read:

mytask.stackHeap = HeapMem_Handle_to_xdc_runtime_IHeap(sdramstack);

I think that should do it for you!

Chris

0 palanivel guruvareddiar over 14 years ago in reply to Chris McCormick

Prodigy 100 points

Hi Todd and chris,

Thanks for the rapid and clear response.

The issue is resolved.

BTW, what is the parameter stack in Task_Params struct is used for?

I tried with the online help for SYS BIOS 6, but in vain.

Thanks again for the help.

Thanks & Best regards

Palanivel Guruvareddiar

0 ToddMullanix over 14 years ago in reply to palanivel guruvareddiar

TI__Guru* 96960 points

Normal 0

Palanivel,

The stack parameter is used if you want to provide the memory for the stack instead of having the Task_create allocate it. Refer to the "Stack Alignment" in the Sysbios API Reference for alignment requirements. You can find it in CCS' Help (it's also referred to as CDOC). Note: the default for stack is null, which means use the heap.

The memory pointed to by the stack variable, can be allocated by you from a Heap or simply be a static global buffer. You can use the #pragma to help place and align the global buffer. For example:

#define STACKSIZE 2048

#pragma DATA_SECTION ( myStack, "EXTMEM_STACK_HEAP");

#pragma DATA_ALIGN (myStack, 8);

Char myStack[STACKSIZE]; // global variable

...

taskParams.stackSize = STACKSIZE;
taskParams.stack = myStack;

If you are creating a heap just to pass into Task_create, you can use the stack parameter and avoid the overhead of the heap. Note: you still place your section in your .cfg file.

Todd

0 palanivel guruvareddiar over 14 years ago in reply to ToddMullanix

Prodigy 100 points

Hi Todd,

Thanks for the detailed answer.

Got the point.

Thanks & Best regards

Palanivel Guruvareddiar

0 aparna subramaniam over 13 years ago in reply to Chris McCormick

Prodigy 110 points

Hi Chris/ Palanivel :

I have a similar problem .Part of the dspbios script in *.cfg file is copied below.

bios.MEM.instance("DDR").base = 0xe0000000;

bios.MEM.instance("DDR").len = 0x00200000;

bios.MEM.instance("DDR").createHeap = 1; /* Just so a label shows in the map */

bios.MEM.instance("DDR").enableHeapLabel = 1;

bios.MEM.instance("DDR").heapLabel = "sMUDDR","asm";

bios.MEM.instance("DDR").heapSize = 0x0008000;

I Reference the section sMUDDR in the .c file using extern. However when I port the above lines of script using sys bios modules and APIs I am

unable to reference the memory section correctly. On going through this post, i found the problem to be similar to mine. However i dont understand

Program.global.sdramstack ? How did you get this field sdramstack?

Sorry i am new to sysbios.

Aparna

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Stack placement for task in SYS BIOS 6