What are the steps to convert
1 - 1001 0111 - 111 1011 1011 1000 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.
1
The next 8 bits contain the exponent:
1001 0111
The last 23 bits contain the mantissa:
111 1011 1011 1000 1001 0000
2. Convert the exponent from binary (from base 2) to decimal (in base 10).
The exponent is allways a positive integer.
1001 0111(2) =
1 × 27 + 0 × 26 + 0 × 25 + 1 × 24 + 0 × 23 + 1 × 22 + 1 × 21 + 1 × 20 =
128 + 0 + 0 + 16 + 0 + 4 + 2 + 1 =
128 + 16 + 4 + 2 + 1 =
151(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 = 151 - 127 = 24
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 1011 1011 1000 1001 0000(2) =
1 × 2-1 + 1 × 2-2 + 1 × 2-3 + 1 × 2-4 + 0 × 2-5 + 1 × 2-6 + 1 × 2-7 + 1 × 2-8 + 0 × 2-9 + 1 × 2-10 + 1 × 2-11 + 1 × 2-12 + 0 × 2-13 + 0 × 2-14 + 0 × 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 + 0.015 625 + 0.007 812 5 + 0.003 906 25 + 0 + 0.000 976 562 5 + 0.000 488 281 25 + 0.000 244 140 625 + 0 + 0 + 0 + 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 + 0.015 625 + 0.007 812 5 + 0.003 906 25 + 0.000 976 562 5 + 0.000 488 281 25 + 0.000 244 140 625 + 0.000 015 258 789 062 5 + 0.000 001 907 348 632 812 5 =
0.966 569 900 512 695 312 5(10)
= -32 993 568
1 - 1001 0111 - 111 1011 1011 1000 1001 0000, a 32 bit single precision IEEE 754 binary floating point representation standard to a decimal number, written in base ten (float) = -32 993 568(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.