Explanation
Performing a bitwise AND operation between a binary number and 0xFE (which is 11111110 in binary) will result in preserving all bits of the original number except for the least significant bit (LSB). The AND operation with 0xFE will set the LSB to 0 and leave the other bits unchanged.
Here's a step-by-step explanation:
Let's assume "R" is an 8-bit binary number, and you want to perform the AND operation with 0xFE:
R: a7 a6 a5 a4 a3 a2 a1 a0 (8 bits)
0xFE: 1 1 1 1 1 1 1 0 (8 bits)
---------------------------
Result: a7 a6 a5 a4 a3 a2 a1 0 (8 bits)
As you can see, each bit in the result is the result of the AND operation between the corresponding bits of "R" and 0xFE. The least significant bit (a0) is always set to 0 because 0xFE has a 0 in its LSB.
So, the effect of performing the AND operation of "R" with 0xFE is to clear the least significant bit of "R" while leaving the other bits unchanged.