4 votes 4 votes A computer has 170 different operations. Word size is 4 Bytes. one word instruction requires two address fields. One address for register and one address for memory. If there are 37 registers then the memory size is ____ (in KB). CO and Architecture co-and-architecture + – Upasana singh asked Oct 16, 2017 • retagged Nov 13, 2017 by Arjun Upasana singh 3.6k views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply Show 2 previous comments Ashwani Kumar 2 commented Oct 16, 2017 reply Follow Share 256 KB ? 0 votes 0 votes sourav. commented Oct 16, 2017 reply Follow Share yes it will be 256 only , $2^{32-(8+6)}B=2^{18}B=256KB$ 0 votes 0 votes rahul sharma 5 commented Nov 7, 2017 reply Follow Share It is not mentioned that it is word or byte addressable?So how can we conclude? 0 votes 0 votes Please log in or register to add a comment.
Best answer 7 votes 7 votes One word siz e= 4 byte =32 bit Now since there are 170 different operations so it can be represented by 8 bit = log2(170) Now since there are 37 registers so it can be represnted by log2(37)= 6 bit and Your instruction has one register and on memory Field So i can say size of instruction = size of operation + size of reg + size of mem(say x) 32=8+6+x x=18bit now memory size is 2^18 word But 1 word is 4 byte so it become 2^18*2^2 = 1MB :) Dexter answered Oct 16, 2017 • selected Oct 16, 2017 by just_bhavana Dexter comment Share Follow See all 0 reply Please log in or register to add a comment.
0 votes 0 votes Size of word = 4B = 32 bit No of register = 37 so 6 bits required for this field No of operations = 170 so 8 bits required for this field No of bits for memory field = 32-(8+6)= 18 Size of memory = 2^18 B = 258 KB Hence 256 KB is correct answer Ashwani Kumar 2 answered Oct 16, 2017 Ashwani Kumar 2 comment Share Follow See all 2 Comments See all 2 2 Comments reply Upasana singh commented Oct 16, 2017 reply Follow Share By default, we consider memory as byte addressable or word addressable? 0 votes 0 votes rishi71662data4 commented Oct 16, 2017 reply Follow Share In GATE it will be mentioned, weather word or byte addressable. In this question, it is mentioned that it is a one word instruction. Hence, word addressable 2 votes 2 votes Please log in or register to add a comment.