How to create Memory dynamically in the DSP ?

rajesh peddi

Prodigy 230 points

Hello Experts,

How to create the memory dynamically in the DSP ?

Thank you,

Raju

over 15 years ago

0 ToddMullanix over 15 years ago

TI__Guru* 96960 points

Hi Raju,

Which version of BIOS are you using?

Do you want to dynamically create a heap which can be used to alloc/free memory?

Todd

0 rajesh peddi over 15 years ago in reply to ToddMullanix

Prodigy 230 points

Hi ToddMullanix,

Bios version is 5_41_00_06.

Yeah i want to create a heap dynamically.

Thank you,

Raju.

0 ToddMullanix over 15 years ago in reply to rajesh peddi

TI__Guru* 96960 points

Hi Raju,

The API is MEM_define(). There is a good description of this function in the DSP/BIOS API Reference Guide. Basically it is the following where the segid can be passed into MEM_alloc/MEM_free. Note, you have to provide the memory with the base parameter.

segid = MEM_define(base, length, attrs);

Parameters
Ptr base; /* base address of new segment */
Uns length; /* length (in MADUs) of new segment */
MEM_Attrs *attrs; /* segment attributes */

Return Value
Int segid; /* ID of new segment */

Todd

0 Brad Griffis over 15 years ago in reply to rajesh peddi

TI__Guru*** 125430 points

The heap size(s) are specified at build time and then one can allocate memory from the heap(s) at run-time. This article gives instructions on how to do so:

http://processors.wiki.ti.com/index.php/Creating_Dynamic_Objects_and_Threads_in_BIOS

0 rajesh peddi over 15 years ago in reply to Brad Griffis

Prodigy 230 points

Hello experts,

i am using linux os. In linux the code composer studio is not installed. how to allocate the heap memory can you explain me.

Thank you,

Raju

0 ToddMullanix over 15 years ago in reply to rajesh peddi

TI__Guru* 96960 points

Raju,

The memory you give to MEM_define can either be static memory (e.g. global Char array) or memory allocated from another heap.

For example

Char bigBuffer[4096];
main()
{
int segid;
...

segid = MEM_define(bigBuffer, 4096, NULL);

main()
{
    int segid;
    Char *bigBuffer;
...
    bigBuffer = MEM_alloc(0, 4096, 0); // segid 0 is the default heap

segid = MEM_define(bigBuffer , 4096, NULL);

As Brad noted, you can also create a heap statically via the configuration file.

You might want to try to build some of the BIOS examples and play with them to get a better feel for DSP/BIOS.

Todd

0 yucun jia70278 over 15 years ago in reply to ToddMullanix

Prodigy 10 points

Hi,

I tried the global array approach as follows but could not get it work.

I use linux (no CCS) and dsp/bios bridge, the DSP source code is in a file containing 3 functions required by DSP/BIOS bridge, i.e., x_y_create(), x_y_delete(), and x_y_excute().

The file looks like:

#include ...

#define ...

Char bigBuffer[4096];

Int segid;

x_y_create()

{ segid = MEM_define(bigBuffer, 4096, NULL); ...}

...

The program can be compiled and run if I comment off the statement of segid = MEM_define(bigBuffer, 4096, NULL), but after including this statement, the program encounters run time error during dsp node creation.

Could Todd or other experts give any hints? Thanks!

Jia

0 ToddMullanix over 15 years ago in reply to yucun jia70278

TI__Guru* 96960 points

Hi Jia,

What is the return from MEM_define? -1 denotes an error.

Do you have dynamic memory heaps enabled (look in the System->MEM->Properties)?

Todd

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How to create Memory dynamically in the DSP ?