Sir, why haven't you considered 0 ( **0**11100010 ) as the sign bit? I calculated the answer as 226.

27 votes

The octal representation of an integer is $(342)_8$. If this were to be treated as an eight-bit integer in an $8085$ based computer, its decimal equivalent is

- $226$
- $-98$
- $76$
- $-30$

38 votes

Best answer

$(3\; 4\; 2)_8 = (011 \; 100 \; 010)_2 = (11100010)_2.$

If we treat this as an 8 bit integer, the first bit becomes sign bit and since it is "1", number is negative. 8085 uses 2's complement representation for integers and hence the decimal equivalent will be $-(00011110)_2 = -30.$

Correct Answer: $D$

If we treat this as an 8 bit integer, the first bit becomes sign bit and since it is "1", number is negative. 8085 uses 2's complement representation for integers and hence the decimal equivalent will be $-(00011110)_2 = -30.$

Correct Answer: $D$

0

@arjun_sin, it is not mentioned anywhere in question, first bit will be signed bit, i am confused here when we consider 1st bit is signed bit and when we ignore 1st bit

1

In this question they have mentioned 8bit integer in an 8085 therefore we are considering 8 bit from LSB to MSB, if nothing is mentioned then we have to consider it as a +ve number.

5

8 bit integer ===> all integers are 8 bits,

if it isn't signed, then we can't represent -ve integers, therefore it should be signed number.

if it isn't signed, then we can't represent -ve integers, therefore it should be signed number.

9 votes

First, write for each decimal equivalent binary code :

since 8 = 2^{3}

write each digit in 3-bit binary

(342)_{8} = (011 100 010)_{2} ignore initial zero

(342)_{8} = (226)_{10} = (11100010)_{2}

since all processor use 2's complement number system(2's complement number system is weighted number system)

so 11100010 is a negative number

11100010 = 100010 = -2^{5} + 2 = -30

correct answer D