The Gateway to Computer Science Excellence
First time here? Checkout the FAQ!
x
+23 votes
1.4k views
In an 11-bit computer instruction format, the size of address field is 4-bits. The computer uses expanding OP code technique and has 5 two-address instructions and 32 one-address instructions. The number of zero-address instructions it can support is ________
asked in CO & Architecture by Veteran (59.4k points)
retagged by | 1.4k views

2 Answers

+34 votes
Best answer
No. of possible instruction encoding = $2^{11} = 2048$

No. of encoding taken by two-address instructions = $5 \times 2^4 \times 2^4 = 1280$

No. of encoding taken by one-address instructions = $32 \times 2^4 = 512$

So, no. of possible zero-address instructions = $2048 - (1280 + 512) = 256$
answered by Veteran (339k points)
selected by
0
what is the logic behind the calculation of no. of 2 address and 3 address instructions ?

@arjun sir @habibkhan
0

Could you generalize this concept for all  the problems because by using this method I am unable to find out the answer to all the questions .

Plz see this.

https://gateoverflow.in/199515/co-addressing

0 votes
Out of 11 bits, 3 bits are for opcode in 2-Address. So 2^3=8 instructions(2-Address) are possible.

But 5 are being used. So 3 are free.

We use these 3 for 1-address instruction by using 4 bits of 1 of the addresses i.e. 3*16=48

Now out of 48 1-address instructions, 32 are being used. So we are left with 16.

Again use these 16 for 0-address instruction by using 4 bits of address i.e. 16*16=256
answered by Junior (681 points)
Answer:

Related questions



Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true

34,814 questions
41,799 answers
119,031 comments
41,445 users