Arduino Zero D0/D1 set output high
You can do this by simply calling the right registers:

Example 1, using a MASK 

D0/D1 are mapped to to PA10 &amp; PA11 on the M0

/* The following ports where selected
    PORT_PA11
    PORT_PA10
    */  
#define MYMASK 0x00000C00

int main (void)
{
    system_init();

    REG_PORT_DIRSET0 = MYMASK; // Direction set to OUTPUT
    REG_PORT_OUTSET0 = MYMASK; // set state of pin(s) to TRUE (HIGH)
    //REG_PORT_OUTCLR0 = MYMASK; // set state of pin(s) to FALSE (LOW)

    while(1){       

    }   
}


Here is another simple example:

/* The following ports where selected
    PORT_PA11
    PORT_PA10
    */  
#define MYMASK 0x00000C00
#define LED1 PORT_PA10
#define LED2 PORT_PA11
int main (void)
{
    system_init();

    REG_PORT_DIRSET0 = LED1 | LED2; // Direction set to OUTPUT
    REG_PORT_OUTSET0 = LED1 | LED2; // set state of pin(s) to TRUE (HIGH)
    //REG_PORT_OUTCLR0 = LED1 | LED2; // set state of pin(s) to FALSE (LOW)
    while(1){   

    }   
}


In the Arduino IDE you can do something like:

#define MYMASK 0x00000C00
void setup() {
  REG_PORT_DIRSET0 = MYMASK; // Direction set to OUTPUT 
}

void loop() {
   REG_PORT_OUTSET0 = MYMASK; // set state of pin(s) to TRUE (HIGH)
   delay(1000);
   REG_PORT_OUTCLR0 = MYMASK; // set state of pin(s) to FALSE (LOW)  
   delay(1000);
}