1. CS-401 Assembly Language Programming
Lecture-4
Computer Architecture & Assembly Language Programming

2. In the Last Lecture
We discussed a program with a listing file.

3. In Today’s Lecture
We will discuss Debugger

4. Physical address calculation

5. Physical Address Calculation
16-bit segment
16-bit offset
20-bit segment +
20-bit offset
20-bit Physical Address

6. 20 –Bit Physical Address Calculation
1 D D D 0
1 D E D 0 +
20 –Bit Physical Address Calculation

7. Segment Base 16 – Bit Segment Register Value 0 0 0 0 0 0 0 0
20 – Bit Segment = 0 Decimal

8. Segment Base 16 – Bit Segment Register Value 0 0 0 1 0 0 0 1
20 – Bit Physical Address = 16 Decimal