Find Bit Within Byte

Hi chayahd99,

IS_SET(IN,BIT_NO)   ((IN) & (1<<(BIT_NO)))

IN is the variable/value in which you need to find the set bit
BIT_NO is the bit number you wish to check for ... 0 is for least significant bit.

Cheers!
Sunnycoder

as you know

AND truth table
0 & 0 = 0
1 & 0 = 0
0 & 1 = 0
1 & 1 = 1

so to find if bit number 4(right to left) is set

   10010101
& 00000100
= 00000100

nonzero result means bit is 1

in the above example I meant bit number 3 ;-)

my question wasn't clear:

I want to check if a specified bit is set within a byte (not as written above).

For example:
In the first byte there are 2 bits set and I want to check if these two bits are set in the second byte. I don't mind if other bits are set in the second byte I just want to know if both bits from the first byte are set.

I'm looking for a generic method that won't require defining a mask for each of the 8 options.

Thanks.

>In the first byte there are 2 bits set and I want to check if these two bits are set in the second byte. I don't mind if other bits
>are set in the second byte I just want to know if both bits from the first byte are set.

Simply AND the two bytes .. if you get non-zero then some of the bits are common ... Or do you wish to know which bits are set .. or whether all bits from byte1 are set in byte2 ... Provide some more clarifications

I agree with sunnycoder in his both posts. He is right either with testing single bit (as macro) or with ANDing operands.