ARM bare metal program - Marquee

Let's look at this piece of C code first

#define GPBCON (*(volatile unsigned long *)0x56000010) //This is the definition of the register. Since the GPB pin is connected to the LED in hardware, if the GPB pin is used, then the relevant register must be defined. This register defines the working mode of the GPB related pin.
#define GPBDAT (*(volatile unsigned long *)0x56000014) //This register is used to give data to the pin.

int main()
{
 GPBCON=0x00000400;
 GPBDAT=0x00000000;
 
 return 0;

}

This is a complete marquee program. GPBUP is the pull-up enable register. When using the pin, it is generally defined as enable invalid.

The address declaration at the beginning of the program can be defined later as #include "2440addr.h". The 2440addr.h file contains the definitions of all register addresses in arm.

/* Address declaration */
#define GPBCON (*(volatile unsigned long *)0x56000010)
#define GPBDAT (*(volatile unsigned long *)0x56000014)
#define GPBUP (*(volatile unsigned long *)0x56000018)

/* Variable declaration */ 
#define uint unsigned int

#define LED0_ON() (GPBDAT &= ~(1<<5))
#define LED1_ON() (GPBDAT &= ~(1<<6))
#define LED2_ON() (GPBDAT &= ~(1<<8) )
#define LED3_ON() (GPBDAT &= ~(1<<10))

#define LED0_OFF() (GPBDAT |= (1<<5))
#define LED1_OFF() (GPBDAT |= (1<<6))
#define LED2_OFF() (GPBDAT |= (1<<8))
#define LED3_OFF() (GPBDAT |= (1<<10))

/* Function declaration */ 
void Delay(uint);

/* Delay function */
void Delay(uint x)
{
 uint i,j,k;
 for(i=0;i   for(j=0;j<0xff;j++)
   for(k=0;k<0xff;k++);
} 

/* Main function */
int Main(void)
{
 GPBCON = (1<<(5*2)) | (1<<(6*2)) | (1<<(8*2)) | (1<<(10*2));//Set the relevant pins of LED0, LED1, LED2 and LED3 to output
 GPBUP = 0xff;
 GPBDAT = (1<<5)| (1<<6) | (1<<8)| (1<<10);
 
 
 while(1)
 {
  LED0_ON();
  Delay(30);
  LED0_OFF();
  LED1_ON();
     Delay(30);
  LED1_OFF();
  LED2_ON();
     Delay(30);
  LED2_OFF();
  LED3_ON();
  Delay(30);
  LED3_OFF();
  Delay(30);
 }
 return 0;
}

There are some software configuration issues here, which I won't mention. Also, the startup code I used cancelled all MMU related content because it is not used in bare metal programs.