source: Documentation/Tutorials/XPS_Intro/code/UserIO_Demo_v1.c

#include "xgpio.h"
#include "warp_userio_v1.h"
#include "xparameters.h"

//Shortcuts for constants in xparameters.h
#define USERIO_DEVICE_ID    XPAR_USER_IO_DEVICE_ID

//Instances of the GPIO and Intc drivers
static XGpio GPIO_UserIO;

//Global variable for tracking active LED outputs
static unsigned int LED_Outputs = 0;

//Function prototypes
unsigned char sevenSegmentMap(unsigned char x);

int main(void)
{
    XStatus Status;
    unsigned char ledDisp = 0;
    
    //Initialize the UserIO GPIO core
    Status = XGpio_Initialize(&GPIO_UserIO, USERIO_DEVICE_ID);

    //We use both channels in the GPIO core- one for inputs, one for outputs
    XGpio_SetDataDirection(&GPIO_UserIO, USERIO_CHAN_INPUTS, USERIO_MASK_INPUTS);
    XGpio_SetDataDirection(&GPIO_UserIO, USERIO_CHAN_OUTPUTS, 0);

    //Make sure the LEDs are all off by default
    XGpio_DiscreteClear(&GPIO_UserIO, USERIO_CHAN_OUTPUTS, USERIO_MASK_OUTPUTS);

    while(1)
    {
        xil_printf("Displaying: %x\r\n", ledDisp);

        //Update the global variable we use to track which LED/segments are currently lit
        // The xps_gpio core doesn't allow outputs to be read from code, so we have to track this internally
        LED_Outputs = (USERIO_MAP_LEDS(ledDisp) | USERIO_MAP_DISPR(ledDisp) | USERIO_MAP_DISPL(ledDisp));
        
        //Set the LEDs & hex displays
        XGpio_DiscreteSet(&GPIO_UserIO, USERIO_CHAN_OUTPUTS, LED_Outputs);

        usleep(600000);

        //Cycle the displays through [0x0,0xF]
        if(ledDisp == 15)
            ledDisp = 0;
        else
            ledDisp++;
    }
    
    return 0;

}

unsigned char sevenSegmentMap(unsigned char x)
{
    switch(x)
    {
        case(0x0) : return 0x007E;
        case(0x1) : return 0x0030;
        case(0x2) : return 0x006D;
        case(0x3) : return 0x0079;
        case(0x4) : return 0x0033;
        case(0x5) : return 0x005B;
        case(0x6) : return 0x005F;
        case(0x7) : return 0x0070;
        case(0x8) : return 0x007F;
        case(0x9) : return 0x007B;

        case(0xA) : return 0x0077;
        case(0xB) : return 0x007F;
        case(0xC) : return 0x004E;
        case(0xD) : return 0x007E;
        case(0xE) : return 0x004F;
        case(0xF) : return 0x0047;
        default : return 0x0000;
    }
}