Is microblaze able to change heap_size?

Forget about xil_malloc() and just use malloc().

-Ben-

But malloc doesn't work in Microblaze. Could you help me?. How can I do it?

Since when? I have never had any problems with it.

From the "LibXil Standard C Libraries" documentation: The MicroBlaze and PPC405 C libraries support all the standard memory management functions such as malloc(), calloc(), free()

There is nothing magical about malloc(). It's just an interface to a dynamically-allocatable wodge of memory. It doesn't have any dependencies on special processor features; in some environments it can make a system call to request more memory from the underlying OS, but with an embedded system it's more common just to have a fixed heap size.

-Ben-

Well I have increased heap_size and it seems ok, but when I add more code to my project it fails again and I know I have quite a lot memory since I have downloaded the app to the sdram with 32MB. I think malloc works abnormally. In some cases I have seen it work fine and in anothers it doesn`t work.

I suppose it has a reason but I don`t know what.

Thanks again for your help.

What evidence do you have that malloc() is not working, vs. something is your code is not working? Do you know that your code works when compiled for another system? The standard C library functions in the Xilinx toolchain are not proprietary. They are basically the same routines you'd get when using any other GNU-based cross-compiler.

So I would first of all try to isolate the failure in your code and see why it is failing. The most likely cause in an embedded system is running out of stack space, rather than heap space. This is particularly true when porting some software from a PC environment to an embedded system, because most PC programmers are extremely lazy about memory management and will happily allocated megabytes of temporary data on the stack without batting an eyelid...

Heap exhaustion is easy to catch because malloc() returns an error code. Stack overflows/corruption are much nastier and can have all sorts of hard-to-track-down side effects.

Cheers,

-Ben-

Well, you are ok. I am porting some software from a PC environment to an embedded system. But I don`t understand this:

- First I crate a simple main.c with a malloc(128*1024) . That is, I reserve memory for 128k. I edit linker script and program runs OK.

- Second I increase my code, adding some lines and four files. But I do ,at the first, the same memory reserve: malloc(128*1024), and I edit the linker script with the same size as the example above. But in this case malloc returns NULL.

I suppose I have to learn quite a lot, but I cannot understand how Malloc works with first example and not for the second one.

But, I must be thankful for your constructive commentary.

Regards, Pablo