Need to measure cycle count using DWT

Please refer to these related articles:

"How can I count the number of instructions executed by the processor in a given time interval?"

    https://developer.arm.com/documentation/ka001253/1-0/?lang=en

"Using DWT and other methods to count executed instructions on Cortex-M"

    https://developer.arm.com/documentation/ka001499/latest 

This code below works for me:

  // Bit mask definitions (*_Msk) are from core_cm3.h

  // To use DWT, you have to set the Trace Enable bit in DEMCR...
  CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;

  // Trace DEMCR might not be writable from CPU (only debugger??)
  if( !(CoreDebug->DEMCR & CoreDebug_DEMCR_TRCENA_Msk) ) {
    GPIO_PinOutSet( LED1 );
    return -1;
  }

  // CYCCNT might not be implemented ?
  if( DWT->CTRL & DWT_CTRL_NOCYCCNT_Msk ) {
    GPIO_PinOutSet( LED1 );
    return -1;
  }
 
  // Reset the cycle counter and enable it, so it starts counting
  DWT->CYCCNT = 0;
  DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;

Note how I use CoreDebug-> where you used DCB->. Where are you getting the macro 'DCB' from?  I don't see it in e.g. core_cm3.h.