Answer to Question #244722 in Electrical Engineering for Mopuri Manjunath

Question

1. In an assignment given on CSE211, a student is assigned the following task
3. Consider PC = last digits of your registration no
4. Place your date of birth including your date and month of birth into the DR
eg: 0108 – 01 date and 08 as month
5. Now perform the below given task
AR  PC
M[AR] DR
IR M[AR]
Explain the contents of the memory after the execution of second instruction.
2. If PC = 789 H , how CPU will fetch the instruction(binary code) from memory using common bus
system explain in detail.

Answer 1

Consider PC = 0190-340

: 0108 – 01 date and 08 as month

The task:

AR  PC

M[AR] DR

IR M[AR]

With this, we can arrange the instructions as follows from the first to the third:

First Instruction D0T4: R Í M[AR] D0T5: AC Í AC ⊕ DR, SCÍ0

Second Instruction: D1T4: DR Í M[AR] D1T5: DR Í AC, AC Í AC + DR D1T6: M[AR] Í AC,

AC Í DR, SC Í 0

Third Instruction: D2T4: DR Í M[AR] D2T5: DR Í AC, AC Í DR D2T6: AC Í (AC D2T7: ACÍ

AC+1 D2T8: AC Í AC + DR, SC Í 0

Contents of the memory after the execution of second instruction.

If PC = 789 H , the CPU will fetch the instruction(binary code) from memory using common bus

based on the mechanism discussed:

From the computation, we determine that 56,536*16 memory has 16 address lines (which means

216 words) with each word having 16 btis. T0, T1, and T2: No change (fetching and decoding)

T3 D7: No change (Register or I/O instructions) Indirect: ID7’ T3: AR(12-15) <--- 0 ID7’ T4:

AR <--M[AR] Direct: I’D7’ T3: PC <-- PC + 1 I’D7’ T4: AR <-- PC So memory reference

instructions would be executed starting from T5.