Function get_twos_complement

libraries/AP_Math/AP_Math.cpp:571–577

get a twos-complement value from the first 'length' bits of a uint32_t With thanks to betaflight */

  With thanks to betaflight
 */
int32_t get_twos_complement(uint32_t raw, uint8_t length)
{
    if (raw & ((int)1 << (length - 1))) {
        return ((int32_t)raw) - ((int32_t)1 << length);
    }
    return raw;
}