2.1.3. Flags in Digital Arithmetic

Try these first

1. 1.

   What does the overflow flag indicate in digital arithmetic?

   Hint

   Think about adding two large numbers.

2. 2.

   What condition sets the zero flag?

   Hint

   Consider what happens when adding opposing values.

3. 3.

   What does the carry flag indicate in unsigned arithmetic?

   • Indicates a negative result
   • Indicates an overflow
   • Indicates a carry out

   Hint

   Think about carrying over in numbers.

4. 4.

   True or False: The zero flag is set only when the result of an operation is not zero.

   • True
   • False

   Hint

   Consider what it means for a result to be zero.

5. 5.

   Consider two 4-bit numbers, 0111 (7) and 0101 (5). Perform the addition. What are the flags set or reset after the operation?

   Hint

   Sum the numbers and analyze each flag accordingly.

6. 6.

   You have two 4-bit signed numbers: 1001 (-7 in two's complement) and 0110 (6). Analyze their addition and describe the flags affected.

   Hint

   Convert to decimal and monitor how each flag reacts to the addition.