[En-Nut-Discussion] heap.c code optimization

[Harald Kipp]

Dusan,

Same code can be found in NutThreadCreate(). As a more
general solution (16-bit boundaries), we may combine it with
Tyou's H8 port, which uses a defined alignment:

     if (0 != (size % MEM_ALIGNMENT)) {
         size += MEM_ALIGNMENT;
         size &= ~((SIZE)MEM_ALIGNMENT-1);
     }

Thus we get

#if MEM_ALIGNMENT > 1
   size = (size + MEM_ALIGNMENT - 1) & ~((size_t)(MEM_ALIGNMENT - 1));
#endif

or, alternatively

#if MEM_ALIGNMENT > 1
   size += MEM_ALIGNMENT - (size & (MEM_ALIGNMENT - 1));
#endif

or create a macro

#define ALIGN_MEM(size)...

Harald

At 22:33 15.01.2005 +0100, you wrote:
>Hi guys,
>
>how do you like sitting following piece of code in your applications ? 
>(os/heap.c:NutHeapAlloc)
>
>>     while ((size & 0x03) != 0)
>>         size++;
>
>What about to change it to
>
>         size = (size + 3) & ~((size_t)0x03);
>
>I do not know exactly how it'll be compiled on various platforms but I 
>feel it can be quicker.
>
>
>Dusan