🐛 Fix the problem of millis()

[Jerrylum]

Summary:

The millis() number reset to zero every 1h 11m 34s and 967ms.

According to the source code:

pros/src/rtos/tasks.c

Lines 2050 to 2062 in 1e07ae9

	uint32_t millis(void)
	{
	uint32_t xTicks;
	/* Critical section required if running on a 16 bit processor. */
	portTICK_TYPE_ENTER_CRITICAL();
	{
	xTicks = xTickCount;
	}
	portTICK_TYPE_EXIT_CRITICAL();
	return xTicks * configTICK_RATE_HZ / 1000;
	}

Ok, so we are using uint32_t and the maximum value is 2^32 = 4294967296
At the same time. 1h 11m and 35s equal to 71*60*1000+35*1000 = 4295000

Please pay attention to line 2061, return xTicks * configTICK_RATE_HZ / 1000;

That equals to 4295000 * 1000 / 1000 -> 4295000000 / 1000 and 4295000000 > 4294967296
The millis() overflow.

Motivation:

Running a program for over an hour.

References (optional):

My time

Test Plan:

• run the test code

void opcontrol() {
	while (1) {
        pros::lcd::print(6, "Time: %d", pros::millis());
        pros::lcd::print(7, "H:%d M:%d S:%d", pros::millis()/1000/60/60,
                                              pros::millis()/1000/60%60,
                                              pros::millis()/1000%60);
        pros::delay(20);
    }
}

[Jerrylum]

100 hours challenge