AVR Freaks

Hello , I am using Atmega128 and 8 shift registers 6D595 the ser_out of each register is connected to the next shift register's ser_in so they form a chain. There is no issue with the hardware it has been tested. I am using 4 16 bit variables to send data to shift registers. the  problem that i am facing is that only once i am able to latch out the values only once .. For example if i send 4 variables as 0x0011,0xFF00,0x3c1d,0x1100 (they can be anything ) then i get the output on my 8 segment panel. but i am only able to update my registers only once . if i try to update them in a loop the program only shows the first value that i had sent to the shift register function

here is what i am doing in my shift out register

<code>

void shift_out(uint16_t data[4])

make latch pin HIGH

for(int x=0;x<3;x++)

{

      for(int i=0;i<16;i++) 

     { 

             set data pin according to data[x] 

            give a low pulse to clock pin then make it high

     }

}

give a low pulse to latch pin then make it high 

</code>

if i call this function once it works perfectly fine 

but if i call it again with different values nothing happens 

please help me i am not sure what else information i am supposed to share.. but i am willing to share anything.. Thanks in advance!! 

I found out that the program doesnt return from my function but keeps on performing this function even if it is not in a loop

void shift_out_data2(uint16_t data1,uint16_t data2,uint16_t data3,uint16_t data4)
{    
    
    
    
    for(int i=0;i<16;i++)
    {
        if(data1 & (1<<(i)))
        PORTC |= (1<<(3));   // data pin
        else
        PORTC &= 0b11110111; // data pin
        
        PORTC |= (1<<(4));   //clock pin        
        _delay_us(10);
        PORTC &= 0b11101111; // clock pin
        
    }
    
    for(int i=0;i<16;i++)    //same loop as above but for next data
    {
        if(data2 & (1<<(i)))
        PORTC |= (1<<(3));
        else
        PORTC &= 0b11110111;
        
        PORTC |= (1<<(4));
        _delay_us(10);
        PORTC &= 0b11101111;
        
    }
    for(int i=0;i<16;i++)
    {
        if(data3 & (1<<(i)))
        PORTC |= (1<<(3));
        else
        PORTC &= 0b11110111;
        
        PORTC |= (1<<(4));
        _delay_us(10);
        PORTC &= 0b11101111;
        
    }
    
    for(int i=0;i<16;i++)
    {
        if(data4 & (1<<(i)))
        PORTC |= (1<<(3));
        else
        PORTC &= 0b11110111;
        
        PORTC |= (1<<(4));
        _delay_us(10);
        PORTC &= 0b11101111;
    }
    PORTC |= 0b00000100;    // latch pin    
      PORTC &= 0b11111011;  //latch pin
    
}