2.1.7. Commonly Used Flags

Try these first

1. 1.

   What does the zero flag indicate?

   Hint

   Consider the output of basic arithmetic operations.

2. 2.

   What happens if an overflow occurs?

   Hint

   Think about the limits of the binary representation.

3. 3.

   What does the carry flag indicate in unsigned arithmetic?

   • 1. Overflow
   • 2. Underflow
   • 3. Carry out of the most significant bit

   Hint

   Consider what happens when adding large numbers.

4. 4.

   True or False: The zero flag is set if the result of an operation is non-zero.

   • True
   • False

   Hint

   Reflect on what zero means in arithmetic operations.

5. 5.

   You have two signed 4-bit numbers, -3 (in 2's complement 1101) and 5 (0101). Calculate their sum, and identify the flags set.

   Hint

   Evaluate using 2's complement rules.

6. 6.

   Write a program flow that considers carry and overflow checks for adding two 8-bit unsigned numbers. Describe the necessary conditional jumps.

   Hint

   Check how to evaluate flags after arithmetic operations.