Linker C6000: how to automatically set a sections size to the free (non allocated) memory?

Alberto Chessa

Hi,

I want, at link time, to allocate automatically all the free remaining RAM memory to a special section to be used as a custom memory pool that adapts its size to the size of unused memory. I tried some SPC arithmetic but I'm not able to work it out.

Something like:

#define RAM_SIZE (512*1024*1024) //512M (EVM)

MEMORY { .... RAM: o=0x80000000, l=RAM_SIZE }

SECTIONS

{

...

GROUP

{

.data

...

.sysmem

.my_memory_pool: align(0x100), type=NOINIT

{

my_memory_pool_begin = . ;

. += END(RAM) - my_memory_pool_begin ; // error: my_memory_pool_begin undefined!!

}

} > RAM

}

I tried also with SIZE(RAM) and literal values but I get always some errors.

over 13 years ago

0 George Mock over 13 years ago

TI__Guru**** 244120 points

You don't need to explicitly construct a section to solve your problem. I'll present my solution as a series of linker command file snippets.

Before either the MEMORY or SECTIONS directives have ...

#define RAM_START 0x80000000
#define RAM_SIZE  0x02000000

_my_heap_size = RAM_START + RAM_SIZE - _my_heap_start;

In the MEMORY directive have ...

RAM:    o = RAM_START   l = RAM_SIZE

The SECTIONS directive will include something similar to ...

GROUP
{
    .stack
    .args
    /* other data memory sections here */
} > RAM, end(_my_heap_start)

You can use the symbols my_heap_start and my_heap_size in your code to set up your custom heap.

Thanks and regards,

-George

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Linker C6000: how to automatically set a sections size to the free (non allocated) memory?