making your own malloc function in C

Question

I need your help in this. I have an average knowledge of C and here is the problem. I am about to use some benchmarks to test some computer architecture stuff (branch misses

Answer 1

This is a very simple approach, which may get you past your 2 mallocs:

static unsigned char our_memory[1024 * 1024]; //reserve 1 MB for malloc
static size_t next_index = 0;

void *malloc(size_t sz)
{
    void *mem;

    if(sizeof our_memory - next_index < sz)
        return NULL;

    mem = &our_memory[next_index];
    next_index += sz;
    return mem;
}

void free(void *mem)
{
   //we cheat, and don't free anything.
}

If required, you might need to align the memory piece you hand back, so e.g. you always give back memory addresses that's on an address that's a multiple of 4, 8, 16 or whatever you require.