小编lar*_*ein的帖子

我使用DWT-> CYCCNT检查了核心周期计数。但与我的预测不同。你能告诉我原因吗？

我的设备是STM32 NUCLEO-L476RG。我只是检查DWT-> CYCCNT。并且只更改了整数分配的次数。

  m_nStart = DWT->CYCCNT;  
  m_nStop = DWT->CYCCNT;
  printf("Cycle diff - assign 0 : %lu\n", m_nStop - m_nStart);

  m_nStart = DWT->CYCCNT;  
  i = 10;
  m_nStop = DWT->CYCCNT;
  printf("Cycle diff - assign 1 : %lu\n", m_nStop - m_nStart); 

  m_nStart = DWT->CYCCNT;  
  i = 10;
  i = 20;
  m_nStop = DWT->CYCCNT;
  printf("Cycle diff - assign 2 : %lu\n", m_nStop - m_nStart); 

  m_nStart = DWT->CYCCNT;  
  i = 10;
  i = 20;
  i = 30;
  m_nStop = DWT->CYCCNT;
  printf("Cycle diff - …