I was curious about that too :) My guess is 16 items (edit: OP says 12) but I'm not an embedded developer, and I'm sure it's hardware-specific. The approach I'

I was curious about that too :) My guess is 16 items (edit: OP says 12) but I'm not an embedded developer, and I'm sure it's hardware-specific. The approach I've seen for larger fixed-sized tables is a free list: when the table is allocated, also initialize an array of the slot numbers, with an associated length index. To allocate, pop the last slot # off the array and decrement the length index. To free, push the slot # onto the end of the array and increment the length index. Checking for a free slot is then just testing for length index > 0.