memory allocation on msmc

Cheng Wang66110

Other Parts Discussed in Thread: SYSBIOS

Hi all,

I wanna allocate a size of memory on MSMC. Currently the only way I know is to use TI extensions. However, I suppose the allocation happens on the ARM side and use gcc compiler. And the allocated memory could be shared by the DSP, as MSMC is shared by ARM and DSP.

However, how can I allocate an array on MSMC from the DSP side, which is compilable by cl6x DSP compiler?

Does there exist a way to do that?

Thanks

Cheng

over 11 years ago

0 lding over 11 years ago

TI__Guru* 95265 points

Something like:

In C code:

#pragma DATA_SECTION(arrayA, ".dataBuffer")
uint32_t arrayA[1024];

Then in your linker command file:

SECTIONS
{
.dataBuffer > MSMCRAM
}

The range of the MSMCRAM either can be defined in linker command file, or from RTSC platform.

Regards, Eric

0 Cheng Wang66110 over 11 years ago in reply to lding

Intellectual 910 points

Thanks, Eric,

Attached is the linker command file I used for KS II. I renamed the suffix to .txt in order to upload it.

Is that the right one for KSII? I was used for KS I, but seems that the L2 and SHRAM is just a subset of KS II.

So in that file, the SHRAM must be the MSMCRAM you showed in your example, right?

Another quick question, If I created an array using malloc(), e.g. int *a = (int *)malloc(n * sizeof(int)), which data section it will be located?

Thanks

Cheng

6064.c6678_unified.txt

0 lding over 11 years ago in reply to Cheng Wang66110

TI__Guru* 95265 points

KS II has 6MB MSMC and 1M L2 per core, you need to check with datasheet to update the memory range. If you use malloc, it is allocated from heap.
Regards, Eric

0 Cheng Wang66110 over 11 years ago in reply to lding

Intellectual 910 points

But where is the heap resided? On MSMC or DDR? From the linker command, I did not find a data section called .heap ? Or heap has another name in the name section? I just wanna control an array allocated using malloc() to either ddr or msmc...

Cheng

0 lding over 11 years ago in reply to Cheng Wang66110

TI__Guru* 95265 points

I found heap can be defined in SYSBIOS, is that working for you? Attached is a .cfg file where defined a heap and placed into DDR.

** Create a Heap.

var HeapMem = xdc.useModule('ti.sysbios.heaps.HeapMem');

var heapMemParams = new HeapMem.Params();

heapMemParams.size = 0x300000;

heapMemParams.sectionName = "systemHeap";

Program.global.heap0 = HeapMem.create(heapMemParams);

/* This is the default memory heap. */

Program.sectMap["systemHeap"] = "DDR3";

Regards, Eric

5074.helloWorld.cfg

0 Cheng Wang66110 over 11 years ago in reply to lding

Intellectual 910 points

Yes, exactly. I also found a probably easier way to define a heap on DDR or MSMC.

According to

TMS320C6000 Optimizing Compiler User’s Guide" (http://www.cs.cmu.edu/afs/cs/academic/class/15745-s07/www/c6xref/compiler_guide.pdf)

Dynamic memory allocation is not a standard part of the C language. The

run-time-support library supplied with the C6000 compiler contains several

functions (such as malloc, calloc, and realloc) that allow you to allocate

memory dynamically for variables at run-time.

Memory is allocated from a global pool, or heap, that is defined in the .sysmem

section. You can set the size of the .sysmem section by using the −heap size

option with the linker command. The linker also creates a global symbol,

__SYSMEM_SIZE, and assigns it a value equal to the size of the heap in

bytes. The default size is 0x400 bytes. For more information on the −heap

option, see section 5.2, Linker Options, on page 5-6.

So I can control the heap on DDR or MSMC by editing .sysmem data section. Is that correct?

Thanks

Cheng

0 lding over 11 years ago in reply to Cheng Wang66110

TI__Guru* 95265 points

Yes, I tried and it worked.

Regards, Eric

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memory allocation on msmc