HALL-FOC---don't understand the mcpwm_foc_hall_detect() function

Hi,

       All I know is that the  mcpwm_foc_hall_detect() function is used to calculate  the initial Angle of  the sector corresponding  to the HALL sensor. The results are stored in  hall_table[].

For the details,  there's something in the code of mcpwm_foc_hall_detect() that I don't understand：

 //--------------------------------------------code section-----------------------------------------------------

  // Forwards

    for (int i = 0;i < 3;i++) {

        for (int j = 0;j < 360;j++) {

            motor->m_phase_now_override = (float)j * M_PI / 180.0;    

            chThdSleepMilliseconds(5);

            int hall = utils_read_hall(motor != &m_motor_1);

            float s, c;

            sincosf(motor->m_phase_now_override, &s, &c);

            sin_hall[hall] += s;

            cos_hall[hall] += c;

            hall_iterations[hall]++;

        }

    }

    // Reverse

    for (int i = 0;i < 3;i++) {

        for (int j = 360;j >= 0;j--) {

            motor->m_phase_now_override = (float)j * M_PI / 180.0;

            chThdSleepMilliseconds(5);

            int hall = utils_read_hall(motor != &m_motor_1);

            float s, c;

            sincosf(motor->m_phase_now_override, &s, &c);

            sin_hall[hall] += s;

            cos_hall[hall] += c;

            hall_iterations[hall]++;

        }

    }

//-----------------------------------------------code section--------------------------------------------------

Q1:  Why use a for loop?

Q2:  Will The HALL state be change on each loop , because of the delay about 5ms？

Q3:  Why do we need to distinguish between Forwards and Reverse?

Q4:  Can you explain this iteration principle? or offer some ideas about math?

Thank you very much.