// ============================================================================
#define DWT_CYCCNT *(volatile uint32_t *)0xE0001004
#define DWT_CONTROL *(volatile uint32_t *)0xE0001000
#define SCB_DEMCR *(volatile uint32_t *)0xE000EDFC


static void
DWT_Init()
{
SCB_DEMCR |= 0x01000000;
DWT_CYCCNT = 0;
DWT_CONTROL|= 1; // enable the counter
}

#define ITM_Port8(n) (*((volatile unsigned char *)(0xE0000000+4*n)))
#define ITM_Port16(n) (*((volatile unsigned short*)(0xE0000000+4*n)))
#define ITM_Port32(n) (*((volatile unsigned long *)(0xE0000000+4*n)))

#define DEMCR (*((volatile unsigned long *)(0xE000EDFC)))
#define TRCENA 0x01000000

struct __FILE { int handle; };
FILE __stdout;
FILE __stdin;

int
fputc(int ch, FILE *f)
{
if (DEMCR & TRCENA)
{
while (ITM_Port32(0) == 0);
ITM_Port8(0) = ch;
}
return(ch);
}
// ============================================================================

// In main():

DWT_Init();

printf("Ehlo world!\n");

#include <stdio.h>

int fputc(int c, FILE *stream)
{
   return(ITM_SendChar(c));
}

typedef struct __FILE FILE;

LDFLAGS += --specs=nano.specs