Control Unit - Q10

+2 votes

A control system uses a control memory of 1024 words of 32 bits each. The microinstruction has three fields which are shown below.

                                      Control word

Control Signals  Status Bits Next Address

The no of different control signal combinations in the system is 131. If vertical microprogramming is used then maximum number of status bits we can have is ---?

asked Jun 8 in Computer Organization by gbmentor (54,290 points)
reshown Jun 9 by gbmentor

3 Answers

0 votes
The answer is 14
answered Jun 9 by soumyadeeppro20 (1,720 points)
0 votes

Vertical Microprogramming used so control bits = log_2{131} = 8

\log_2(131) = 8 \log_2(S)=s \log_2(1024)=10

Control memory size given,

{1024\times 32} = 2^{15}bits or 2^{12} Bytes

Control word size = total bits = 8+s+10

Control memory = \frac{\text{Control Word Size} \times \text{\# of words}}{\text{Byte size}}

2^{12} = \frac{(18+s)\times 2^{10}}{8}

2^{15} = (18+s)\times 2^{10}

32= 18+s

s= 14

So status bits = 14

 

 

answered Jun 9 by 23rishiyadavpro20 (6,590 points)
0 votes
10+8=18

32-18=14 so 14 is correct one
answered Jun 9 by tsnikhilsharmagate2018 (19,690 points)
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