Bit SHIFT ISSUES

[lodey]

Hi there,

I am just looking for some advice on Bit shifting.
I have a program that will split a 32bit into its 4 bytes. This works to a certain extent:


I get the following when i run the snippet of code below:

Original HEX NUMBER: CD53BB10;

BYTE1: CD
BYTE2 : 53
BYTE3: BB
BYTE4: 1

#include <stdio.h>
#include <stdlib.h>

int main(void)

    {
              
   	unsigned int n = 0xCD53BB10;
	unsigned int shift =0xFF000000 ;
	unsigned int byte1,byte2,byte3,byte4;
	
	
	
    printf("Original Hex Number: %X\n\n\n",n);
        byte1=(n ) & shift;
	byte1  = byte1 >> 24;
	printf("\nByte1 =%X",byte1);

    shift = 0xFF0000;
        byte2=(n ) & shift;
	byte2  = byte2 >> 16;
        printf("\nByte2 =%X",byte2);
    
    shift = 0xFF00;
        byte3=(n ) & shift;
	byte3  = byte3 >> 8;
        printf("\nByte3 =%X",byte3);
    
    shift = 0xFF;
        byte4=(n ) & shift;
	byte4  = byte4 >> 4;
        printf("\nByte4 =%X",byte4);
    


printf("\n\n");


system("pause");
	
    
    return 0;
	
}

One thing that I am stuck on is the shifting off the hex number 0xFF000000. The only way that I can get it to work is to manually input the number with the last 2 LSB taken off as in the code above. How do i do this automatically? Also when i try and retrieve the last 2 bytes i only get 1 character printed out...

thanks in advance

[whiteflags]

I think your only mistake is that you shifted the last byte to the right by a nibble, resulting in an answer of 0x1.

As for your other question, observe that a byte is actually 8 bits.

#include <stdio.h>
int main(void)
{
    unsigned x;
    for ( x = 0xcd53bb10; x > 0; x >>= 8 )
    {
        printf( "0x%x\n", x );
    }
    return 0;
}

#if 0
0xcd53bb10
0xcd53bb
0xcd53
0xcd
#endif

So now you know how to adjust the shift.