How to set bits 4-7 without changing bits 0-3

[thinksmart]

Hi all,
I am gettting an unsigned integer from a table and i have to set that integer to a byte from the bits 4-7 since the bits 0-3 is already occupied, i dont want to disturb the bits 0-3 . the integer value is always less than 8. Can any1 help me out by simple example

[thinksmart]

i think i need to give still a better explanation, my bit position is like this 0000 0111 , now i need to get an integer which is less than 8 and if it is 5 it shud be like this 0101 0111. my 0111 should not be disturbed.

[horace1]

Hi all,
I am gettting an unsigned integer from a table and i have to set that integer to a byte from the bits 4-7 since the bits 0-3 is already occupied, i dont want to disturb the bits 0-3 . the integer value is always less than 8. Can any1 help me out by simple example

have a look at
http://www.thescripts. com/forum/thread590930.ht ml

[thinksmart]

have a look at
http://www.thescripts. com/forum/thread590930.ht ml

y= ((x >> 4)& 0x0f) | ((x << 4) & 0xf0);

???? can you explain me please abt the above code, thanks in advance

[horace1]

y= ((x >> 4)& 0x0f) | ((x << 4) & 0xf0);

???? can you explain me please abt the above code, thanks in advance

we are swoping bits 0 to 3 and bits 4 to 7 of a byte

((x >> 4)& 0x0f)

shifts x 4 bits right and ANDs by 0x0f to get bits 0 to 3

((x << 4) & 0xf0)

shifts x 4 bits left and ANDs by 0xf0 to get bits 4 to 7

the result of the above operations is then ORed together to get bits 0 to 7

y= ((x >> 4)& 0x0f) | ((x << 4) & 0xf0);

and the result is assigned to y

[thinksmart]

we are swoping bits 0 to 3 and bits 4 to 7 of a byte

((x >> 4)& 0x0f)

shifts x 4 bits right and ANDs by 0x0f to get bits 0 to 3

((x << 4) & 0xf0)

shifts x 4 bits left and ANDs by 0xf0 to get bits 4 to 7

the result of the above operations is then ORed together to get bits 0 to 7

y= ((x >> 4)& 0x0f) | ((x << 4) & 0xf0);

and the result is assigned to y

Thank you very much my friend, i got the required answer, thanks a lot