[atomthreads] uint32 queues parameters and indexes

[Pascal SCLAFER]

Thank you for your project. I use it successfully for my professional activities and it works very well.

typedef struct atom_queue
{
    ATOM_TCB *  putSuspQ;       /* Queue of threads waiting to send */
    ATOM_TCB *  getSuspQ;       /* Queue of threads waiting to receive */
    uint8_t *   buff_ptr;       /* Pointer to queue data area */
    uint32_t    unit_size;      /* Size of each message */
    uint32_t    max_num_msgs;   /* Max number of storable messages */
    uint32_t    insert_index;   /* Next byte index to insert into */
    uint32_t    remove_index;   /* Next byte index to remove from */
    uint32_t    num_msgs_stored;/* Number of messages stored */
} ATOM_QUEUE;


Atomthreads is designed to work with very small micro-controllers.






Is there a reason for using 32 bits integers that I've not understood?


I think that the queues should be modified as below:

typedef struct atom_queue
{
    ATOM_TCB *  putSuspQ;       /* Queue of threads waiting to send */
    ATOM_TCB *  getSuspQ;       /* Queue of threads waiting to receive */
    uint8_t *   buff_ptr;       /* Pointer to queue data area */
    uint8_t    unit_size;      /* Size of each message */
    uint8_t    max_num_msgs;   /* Max number of storable messages */
    uint16_t    insert_index;   /* Next byte index to insert into */
    uint16_t    remove_index;   /* Next byte index to remove from */
    uint8_t    num_msgs_stored;/* Number of messages stored */
} ATOM_QUEUE;


extern uint8_t atomQueueDelete (ATOM_QUEUE *qptr);



It makes a big difference in terms of code size, code speed and stack usage.


Best regards,

Pascal

Today, I was looking for bottlenecks in one of my program, and I found that you use int32 integers in the AtomQueue module. 32 bits integers are slow to compute, and can take a lot of memory resources (stack). For example, there is in "queue_insert" a uint32*uint32 multiplication, and 32 bits multiplications are a pain in the ass on a 8bit micro-controller. Moreover, on small micro controllers, there is often less than 4kb memory. That's why using a 32 bits integer for a queue length is pretty unuseful. extern uint8_t atomQueueCreate (ATOM_QUEUE *qptr, uint8_t *buff_ptr, uint8_t unit_size, uint8_t max_num_msgs); extern uint8_t atomQueueGet (ATOM_QUEUE *qptr, int32_t timeout, uint8_t *msgptr); extern uint8_t atomQueuePut (ATOM_QUEUE *qptr, int32_t timeout, uint8_t *msgptr);

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