In the standard IEEE 754 single precision floating point representation, there is 1 bit for sign, 23 bits for fraction and 8 bits for exponent. What is the precision in terms of the number of decimal digits?  

In the standard IEEE 754 single precision floating point representation, there is 1 bit for sign, 23 bits for fraction and 8 bits for exponent. What is the precision in terms of the number of decimal digits?   Correct Answer 7

The correct answer is "option 3".

CONCEPT:

The floating-point representation of a number has three parts:

1. Sign of Mantissa - represent the sign of number {0 - negative, 1 - positive}

2. Exponent - represent both positive & negative exponent.

Bias is added to the actual exponent in order to get stored, exponent.

3.Normalised Mantissa - represent the digits with only one "1" to the left of the decimal.

The value of the Normalised number is (-1)S x 1.ME-127

Eg. The floating-point representation for number 85.125:

1.Binary representation of 85.125 → 1010101.001 or 1.010101001 x 26

2.Sign bit → 0 (positive no.)

3.Normalised Mantissa → 010101001

4.Exponent →  127 + 6 = 133  {Bias → 127}

Precision can be by 1.M, so M+1 is used to represent the precise number

23 bits + 1 = 24 bits

According to the formula:

BaseXno. of digits = BaseYno. of digits 

224 = 10x

24 = x log210

x = 7.22

Hence,  the precision in terms of the number of decimal digits is 7  

Related Questions

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How far is point 'R' from Point 'T'? Statement (I): Point 'R' is 5 metres to the north of point 'M'. Point 'U' is 4 metres to the east of point 'R'. Point 'T' is to the west of point 'R' such that points 'U' 'R' and 'T' form a straight line of  metres. Statement (II): Point 'Z' is metres to the south of point 'T'. Point 'U' is  metres to the east of point 'T'. Point 'M' is  metres to the east of point 'Z'. Point 'R' is  metres to the north of point 'M'. Point 'R' lies on the line formed by joining points 'T' and 'U'.
If we decide to stay away from IEEE 754 format by making our Exponent field 10 bits wide and our Mantissa field 21 bits wide, then which of the following statement is TRUE?