How to configure the alignment parameter for heap multi-buf

Hi Thomas,

1. Yes

2. An alignment of 2 means even addresses. Note that HeapMultiBuf is a collection of HeapBufs, each HeapBuf manages a buffer, and the align parameter in HeapBuf_Params for each buffer in the HeapMultiBuf determines the alignment of each block in the buffer. If you dynamically create the HeapMultiBuf, you are responsible for providing buffers that are aligned to match the align parameter for each HeapBuf. See the HeapBuf_Params documentation for details.

3. The M3 is 8-bit-byte-addressable, so I don't think there is any restriction at that level.

4. Allocation from a HeapMultiBuf will return a block from the first buffer which has: a) a block size that is >= to the requested size AND b) an alignment that is >= to the requested alignment. So if Memory_alloc() is invoked with an argument of align=0, that simply means it will return a block from the first buffer that fulfills the block size requirement.

5. HeapMultiBuf is useful when you have algorithms/peripherals that work with buffers of different alignment in a system. For example, the DMA might be more efficient when dealing with 32-bit aligned buffers, whereas an image encoder might want buffers that are aligned to the size of macroblocks. You want the ability to allocate buffers of various alignment while keeping fragmentation in check and minimizing wasted space.

Best regards,
Vincent