/* Producer Process - Shared Memory */
item next_produced;
while (true) {
    /* produce an item in next produced */
    while (((in + 1) % BUFFER_SIZE) == out)
        ; /* do nothing - buffer is full */
    buffer[in] = next_produced;
    in = (in + 1) % BUFFER_SIZE;
}

/* Consumer Process - Shared Memory */
item next_consumed;
while (true) {
    while (in == out)
        ; /* do nothing - buffer is empty */
    next_consumed = buffer[out];
    out = (out + 1) % BUFFER_SIZE;
    /* consume the item in next consumed */
}