question for XMC1300 LLD libary

the following codes are extrated form LLD driver, which the filed name is "system_XMC1300.c"
which guy can tell me why do this operating?

Clock = ((uint32_t)ClockVal) * KHZ_MULTIPLIER;
Clock = Clock >> DCO_DCLK_DIVIDER;[/I][/B]



void SystemCoreClockUpdate(void)
{
uint32_t IDIV, FDIV, CLKCR, Clock;

CLKCR = SCU_CLK -> CLKCR;
IDIV = (CLKCR & SCU_CLK_CLKCR_IDIV_Msk) >> SCU_CLK_CLKCR_IDIV_Pos;
FDIV = (CLKCR & SCU_CLK_CLKCR_FDIV_Msk) >> SCU_CLK_CLKCR_FDIV_Pos;

if(IDIV)
{
/* Divider is enabled and used */
if(0 == FDIV)
{
/* No fractional divider, so MCLK = DCO_Clk / (2 * IDIV) */
Clock = MCLK_MHZ / IDIV;
}
else
{
/* Both integer and fractional divider must be considered */
/* 1. IDIV + FDIV/256 */
Q_24_8 FDiv_IDiv_Sum = (IDIV << FRACBITS) + FDIV;

/* 2. Fixed point division Q24.8 / Q9.8 = Q15.0 */
Q_15_0 ClockVal = (DCO_DCLK_MULTIPLIER << FRACBITS)/ FDiv_IDiv_Sum;
Clock = ((uint32_t)ClockVal) * KHZ_MULTIPLIER;
Clock = Clock >> DCO_DCLK_DIVIDER;
}
}
else
{
/* Divider bypassed. Simply divide DCO_DCLK by 2 */
Clock = MCLK_MHZ;
}

/* Finally with the math class over, update SystemCoreClock */
SystemCoreClock = Clock;
}