What are the steps to convert
1 - 0101 0101 - 101 1110 0000 0000 0010 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.
1
The next 8 bits contain the exponent:
0101 0101
The last 23 bits contain the mantissa:
101 1110 0000 0000 0010 0010
2. Convert the exponent from binary (from base 2) to decimal (in base 10).
The exponent is allways a positive integer.
0101 0101(2) =
0 × 27 + 1 × 26 + 0 × 25 + 1 × 24 + 0 × 23 + 1 × 22 + 0 × 21 + 1 × 20 =
0 + 64 + 0 + 16 + 0 + 4 + 0 + 1 =
64 + 16 + 4 + 1 =
85(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 = 85 - 127 = -42
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 1110 0000 0000 0010 0010(2) =
1 × 2-1 + 0 × 2-2 + 1 × 2-3 + 1 × 2-4 + 1 × 2-5 + 1 × 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 + 1 × 2-18 + 0 × 2-19 + 0 × 2-20 + 0 × 2-21 + 1 × 2-22 + 0 × 2-23 =
0.5 + 0 + 0.125 + 0.062 5 + 0.031 25 + 0.015 625 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0.000 003 814 697 265 625 + 0 + 0 + 0 + 0.000 000 238 418 579 101 562 5 + 0 =
0.5 + 0.125 + 0.062 5 + 0.031 25 + 0.015 625 + 0.000 003 814 697 265 625 + 0.000 000 238 418 579 101 562 5 =
0.734 379 053 115 844 726 562 5(10)
= -0.000 000 000 000 394 352 139 918 702 215 837 242 86
1 - 0101 0101 - 101 1110 0000 0000 0010 0010, a 32 bit single precision IEEE 754 binary floating point representation standard to a decimal number, written in base ten (float) = -0.000 000 000 000 394 352 139 918 702 215 837 242 86(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.