ITPEC FE Morning October 2022 Question 1

Setting the Least Significant Bit — use OR with a bitmask to force a specific bit to 1.

To set the LSB of an 8-bit integer to 1 without changing other bits, perform bitwise OR with 00000001.

• •x OR 0 = x — unchanged bits
• •x OR 1 = 1 — forced to 1

Why not others:
- (a) AND 00000001 — clears all bits except LSB (x AND 0 = 0)
- (b) NAND 11111110 — NAND = NOT(AND), inverts the result, corrupts other bits
- (d) XOR 00000001 — toggles LSB instead of setting it (flips 1 → 0)

Key rule: OR sets bits, AND clears bits, XOR toggles bits.

AI-generated — may contain errors