What are the steps to convert
0 - 1111 0111 - 111 1100 1000 1101 1001 0000, 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.
0
The next 8 bits contain the exponent:
1111 0111
The last 23 bits contain the mantissa:
111 1100 1000 1101 1001 0000
2. Convert the exponent from binary (from base 2) to decimal (in base 10).
The exponent is allways a positive integer.
1111 0111(2) =
1 × 27 + 1 × 26 + 1 × 25 + 1 × 24 + 0 × 23 + 1 × 22 + 1 × 21 + 1 × 20 =
128 + 64 + 32 + 16 + 0 + 4 + 2 + 1 =
128 + 64 + 32 + 16 + 4 + 2 + 1 =
247(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 = 247 - 127 = 120
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).
111 1100 1000 1101 1001 0000(2) =
1 × 2-1 + 1 × 2-2 + 1 × 2-3 + 1 × 2-4 + 1 × 2-5 + 0 × 2-6 + 0 × 2-7 + 1 × 2-8 + 0 × 2-9 + 0 × 2-10 + 0 × 2-11 + 1 × 2-12 + 1 × 2-13 + 0 × 2-14 + 1 × 2-15 + 1 × 2-16 + 0 × 2-17 + 0 × 2-18 + 1 × 2-19 + 0 × 2-20 + 0 × 2-21 + 0 × 2-22 + 0 × 2-23 =
0.5 + 0.25 + 0.125 + 0.062 5 + 0.031 25 + 0 + 0 + 0.003 906 25 + 0 + 0 + 0 + 0.000 244 140 625 + 0.000 122 070 312 5 + 0 + 0.000 030 517 578 125 + 0.000 015 258 789 062 5 + 0 + 0 + 0.000 001 907 348 632 812 5 + 0 + 0 + 0 + 0 =
0.5 + 0.25 + 0.125 + 0.062 5 + 0.031 25 + 0.003 906 25 + 0.000 244 140 625 + 0.000 122 070 312 5 + 0.000 030 517 578 125 + 0.000 015 258 789 062 5 + 0.000 001 907 348 632 812 5 =
0.973 070 144 653 320 312 5(10)
= 2 622 660 073 920 587 003 968 150 215 447 281 664
0 - 1111 0111 - 111 1100 1000 1101 1001 0000, a 32 bit single precision IEEE 754 binary floating point representation standard to a decimal number, written in base ten (float) = 2 622 660 073 920 587 003 968 150 215 447 281 664(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.