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How is Heap2.c allocating memory ?

Posted by Angel Eyes on August 24, 2008

I am trying to port FREERTOS to Samsung S3C4510 processor as I had mentioned in my previous posts . I went through the heap_2.c file . But I am unable to understand , how without the help of the linker , memory is allocated . From where does heap_2.c get to know from where to allocsate stack space , it has to know the memory map somehow ? How is it accomplished ?
Thank you.

RE: How is Heap2.c allocating memory ?

Posted by Dave on August 24, 2008
Heap2 just uses a large array of memory that is dimensioned using the configTOTAL_HEAP_SIZE compile time option.

RE: How is Heap2.c allocating memory ?

Posted by Angel Eyes on August 24, 2008
Yes, saw the declaration in FreeRTOSConfig.h now , thanks .

So we can not actually call it Dynamic memory allocation ? Moreover whether we use it or not that part of the memory is always allocated , right ? So for any number of tasks the allocation is the same .

Also I want to understand the TCB allocation and the scheduler code, the code is very well commented , but there are areas where I am finding it a bit difficult to follow the logic . Are the comments in the code the only way to understand the code flow or is there any other way , is there some documentation in FreeRTOS.org that I am missing out ? I mean what do I need to do if I want to understand the entire source code ?



RE: How is Heap2.c allocating memory ?

Posted by Dave on August 24, 2008
It is an area of memory that is reserved for use by the heap through calls to pvPortMalloc and vPortFree in exactly the same way that the linker script is often used to reserve a portion of memory for use by malloc and free.


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