What are the steps to convert
0 - 1111 1000 - 100 0000 0000 0000 0100 0010, 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 1000
The last 23 bits contain the mantissa:
100 0000 0000 0000 0100 0010
2. Convert the exponent from binary (from base 2) to decimal (in base 10).
The exponent is allways a positive integer.
1111 1000(2) =
1 × 27 + 1 × 26 + 1 × 25 + 1 × 24 + 1 × 23 + 0 × 22 + 0 × 21 + 0 × 20 =
128 + 64 + 32 + 16 + 8 + 0 + 0 + 0 =
128 + 64 + 32 + 16 + 8 =
248(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 = 248 - 127 = 121
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).
100 0000 0000 0000 0100 0010(2) =
1 × 2-1 + 0 × 2-2 + 0 × 2-3 + 0 × 2-4 + 0 × 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 + 1 × 2-17 + 0 × 2-18 + 0 × 2-19 + 0 × 2-20 + 0 × 2-21 + 1 × 2-22 + 0 × 2-23 =
0.5 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0.000 007 629 394 531 25 + 0 + 0 + 0 + 0 + 0.000 000 238 418 579 101 562 5 + 0 =
0.5 + 0.000 007 629 394 531 25 + 0.000 000 238 418 579 101 562 5 =
0.500 007 867 813 110 351 562 5(10)
= 3 987 704 903 589 651 384 496 545 876 443 922 432
0 - 1111 1000 - 100 0000 0000 0000 0100 0010, a 32 bit single precision IEEE 754 binary floating point representation standard to a decimal number, written in base ten (float) = 3 987 704 903 589 651 384 496 545 876 443 922 432(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.