What are the steps to convert
1 - 0101 1000 - 101 0100 0000 0000 0000 1000, a 32 bit single precision IEEE 754 binary floating point representation standard to decimal?
1. Identify the elements that make up the binary representation of the number:
The first bit (the leftmost) indicates the sign,
1 = negative, 0 = positive.
1
The next 8 bits contain the exponent:
0101 1000
The last 23 bits contain the mantissa:
101 0100 0000 0000 0000 1000
2. Convert the exponent from binary (from base 2) to decimal (in base 10).
The exponent is allways a positive integer.
0101 1000(2) =
0 × 27 + 1 × 26 + 0 × 25 + 1 × 24 + 1 × 23 + 0 × 22 + 0 × 21 + 0 × 20 =
0 + 64 + 0 + 16 + 8 + 0 + 0 + 0 =
64 + 16 + 8 =
88(10)
3. Adjust the exponent.
Subtract the excess bits: 2(8 - 1) - 1 = 127,
that is due to the 8 bit excess/bias notation.
The exponent, adjusted = 88 - 127 = -39
4. Convert the mantissa from binary (from base 2) to decimal (in base 10).
The mantissa represents the fractional part of the number (what comes after the whole part of the number, separated from it by a comma).
101 0100 0000 0000 0000 1000(2) =
1 × 2-1 + 0 × 2-2 + 1 × 2-3 + 0 × 2-4 + 1 × 2-5 + 0 × 2-6 + 0 × 2-7 + 0 × 2-8 + 0 × 2-9 + 0 × 2-10 + 0 × 2-11 + 0 × 2-12 + 0 × 2-13 + 0 × 2-14 + 0 × 2-15 + 0 × 2-16 + 0 × 2-17 + 0 × 2-18 + 0 × 2-19 + 1 × 2-20 + 0 × 2-21 + 0 × 2-22 + 0 × 2-23 =
0.5 + 0 + 0.125 + 0 + 0.031 25 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0.000 000 953 674 316 406 25 + 0 + 0 + 0 =
0.5 + 0.125 + 0.031 25 + 0.000 000 953 674 316 406 25 =
0.656 250 953 674 316 406 25(10)
= -0.000 000 000 003 012 702 934 346 300 764 900 661 29
1 - 0101 1000 - 101 0100 0000 0000 0000 1000, a 32 bit single precision IEEE 754 binary floating point representation standard to a decimal number, written in base ten (float) = -0.000 000 000 003 012 702 934 346 300 764 900 661 29(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.