How can I get the free run value of timer?

I have the DK-TM4C129x evaluation board on which actually XM4C129XNCZADI 137AK3SW G1 is mounted.

Now, I have been start porting netMF 4.3 PK to TM4C129x controller.

I could not get the correct free run value from timer0. Is this bug of chip(XM4C129x)?

I have implemented  test code to get the value by using snap shot function of times0 as following.

My test code

BOOL HAL_Time_Initialize()
{
	//
	// Initialize the graphics context.
	//
	GrContextInit(&g_sContext, &g_sKentec320x240x16_SSD2119);

	//
	// Draw the application frame.
	//
	FrameDraw(&g_sContext, "timers");
	UARTprintf("FrameDraw\n");

	//
	// Initialize timer status display.
	//
	GrStringDraw(&g_sContext, "Timer 0:", -1, 100, 108, 0);

	//
	// Enable the peripherals used by this example.
	//
	MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);

	//
	// Enable processor interrupts.
	//
	MAP_IntMasterEnable();

	//
	// Configure the two 32-bit periodic timers.
	//
	MAP_TimerConfigure(TIMER0_BASE, TIMER_CFG_PERIODIC);

	uint32_t ui32Config = HWREG(TIMER0_BASE + TIMER_O_TAMR);

	HWREG(TIMER0_BASE + TIMER_O_TAMR) = ui32Config | TIMER_TAMR_TASNAPS;
		
	ui32Config = HWREG(TIMER0_BASE + TIMER_O_TBMR);

	HWREG(TIMER0_BASE + TIMER_O_TBMR) = ui32Config | TIMER_TBMR_TBSNAPS;

		
	MAP_TimerLoadSet(TIMER0_BASE, TIMER_A, SYSTEM_CLOCK_HZ / 2); //for test only 0.5sec, finally will be set to 1us.

	//
	// Setup the interrupts for the timer timeouts.
	//
	MAP_IntEnable(INT_TIMER0A);
	MAP_TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT);

	//
	// Enable the timers.
	//
	MAP_TimerEnable(TIMER0_BASE, TIMER_A);

	return CPU_INTC_ActivateInterrupt(INT_TIMER0A, Timer0IntHandler, 0);
}

void Timer0IntHandler(void* param)
{
	MAP_IntMasterDisable();
	//
	// Clear the timer interrupt.
	//
	MAP_TimerIntClear(TIMER0_BASE, TIMER_TIMA_TIMEOUT);

	gu64LastValue = TimerFreeRunValueGet(TIMER0_BASE, TIMER_A);

	if (HAL_Time_CurrentTicks() >= gu64NextEvent)
	{
		HAL_COMPLETION::DequeueAndExec();
	}
	
	UARTprintf("Timer A=0x%x\n\r", HWREG(TIMER0_BASE + TIMER_O_TAV));
	UARTprintf("Timer B=0x%x\n\r", HWREG(TIMER0_BASE + TIMER_O_TBV));
	//
	// Toggle the flag for the first timer.
	//
	HWREGBITW(&g_ui32Flags, 0) ^= 1;

	//
	// Update the interrupt status on the display.
	//

	GrStringDraw(&g_sContext, (HWREGBITW(&g_ui32Flags, 0) ? "1" : "0"), -1, 195, 108, 1);

	MAP_IntMasterEnable();
}

Serial Terminal Output

A=0x39384d4
B=0x393
A=0x39384d4
B=0x393
A=0x39384d4
B=0x393
.

.

.

.

Does anybody knows that free run value is not changed?