模拟运行的代码时间和实际运行的代码时间非常不同是什么原因导致的？

RCC- gt;APB2ENR = 0x0845;         //使能TIM1和GPIOA/E和AFIO时钟
GPIOA- gt;CRH = 0x0B;         //PA8,9配置为复用推挽输出，50MHz
TIM1- gt;ARR = 0xffff;         //ARR为最大值，使用CCR1和CCR2的比较匹配事件来产生中断
TIM1- gt;DIER = 0x06;         //使能中断CC1IE和CC2IE
TIM1- gt;CCMR1 = 0x3030;         //CH1和CH2都是输出比较模式（翻转）
TIM1- gt;BDTR = 0x8000;         //使能MOE主输出
TIM1- gt;CCER |= TIM_CCER_CC1E;         //使能CC1E输出
TIM1- gt;CR1 |= TIM_CR1_CEN;         //使能定时器
CCR_Acc_x = 562;
CCR_Acc_y = 18000;
TIM1- gt;CCR1 = CCR_Acc_x;
TIM1- gt;CCR2 = CCR_Acc_y;
TIM1- gt;CCR3 = 0xffff;
TIM1- gt;CCR4 = 0xffff;
NVIC_SetPriorityGrouping(4); //3 bits preemption
NVIC_SetPriority(TIM1_CC_IRQn, 0); //highest
NVIC_EnableIRQ(TIM1_CC_IRQn);
DBGMCU- gt;CR |= DBGMCU_TIM1_STOP;
while(1)
{
}

TIM1_SR_mask = TIM1- gt;SR;
if (TIM1_SR_mask  amp; TIM_SR_CC1IF)        //CC1IF
{

TIM1- gt;SR = ~TIM_SR_CC1IF;

TIM1- gt;CCR1 = TIM1- gt;CCR1 + CCR_Acc_x;

}
if (TIM1_SR_mask  amp; TIM_SR_CC2IF)        //CC2IF
{

TIM1- gt;SR = ~TIM_SR_CC2IF;

}
TIM1_SR_mask = TIM1- gt;SR;
if (TIM1_SR_mask  amp; TIM_SR_CC1IF)        //CC1IF
{

NVIC_SetPendingIRQ(TIM1_CC_IRQn);

}
if (TIM1_SR_mask  amp; TIM_SR_CC2IF)        //CC2IF
{

NVIC_SetPendingIRQ(TIM1_CC_IRQn);

}