Explain the operational purpose of the Code Segment (CS), Data Segment (DS), Stack Segment (SS), and Extra Segment (ES).

You're asking for Q5b and Q5c from the image.

Q5b. What information is conveyed when Qs1 and Qs0 are 01?

In the Intel 8086 microprocessor, the Queue Status bits (QS1 and QS0) are used to indicate the status of the instruction queue. These bits are output by the Bus Interface Unit (BIU) to the Execution Unit (EU).

When $\text{QS1} = 0$ and $\text{QS0} = 1$ (i.e., $\text{QS1QS0} = 01_2$), it indicates that the first byte of an opcode has been fetched from the queue. This means the Execution Unit is about to begin processing a new instruction.

Q5c. Calculate the physical address for fetching the next instruction to be executed in 8086.

To calculate the physical address for fetching the next instruction in the 8086 microprocessor, we use the contents of the Code Segment (CS) register and the Instruction Pointer (IP) register. The formula for physical address calculation in the 8086's segmented memory model is:

$$\text{Physical Address} = (\text{Segment Register} \times 10\text{H}) + \text{Offset Register}$$

In this case, for fetching the next instruction:

• The Segment Register is the Code Segment (CS).
• The Offset Register is the Instruction Pointer (IP).

The problem does not provide specific values for CS and IP. Let's assume typical example values to demonstrate the calculation.

Assumption:

• Let $\text{CS} = 1234\text{H}$
• Let $\text{IP} = 5678\text{H}$