What are the steps to convert
1 - 1111 1000 - 101 1000 1001 0100 1101 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:
1111 1000
The last 23 bits contain the mantissa:
101 1000 1001 0100 1101 1000
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).
101 1000 1001 0100 1101 1000(2) =
1 × 2-1 + 0 × 2-2 + 1 × 2-3 + 1 × 2-4 + 0 × 2-5 + 0 × 2-6 + 0 × 2-7 + 1 × 2-8 + 0 × 2-9 + 0 × 2-10 + 1 × 2-11 + 0 × 2-12 + 1 × 2-13 + 0 × 2-14 + 0 × 2-15 + 1 × 2-16 + 1 × 2-17 + 0 × 2-18 + 1 × 2-19 + 1 × 2-20 + 0 × 2-21 + 0 × 2-22 + 0 × 2-23 =
0.5 + 0 + 0.125 + 0.062 5 + 0 + 0 + 0 + 0.003 906 25 + 0 + 0 + 0.000 488 281 25 + 0 + 0.000 122 070 312 5 + 0 + 0 + 0.000 015 258 789 062 5 + 0.000 007 629 394 531 25 + 0 + 0.000 001 907 348 632 812 5 + 0.000 000 953 674 316 406 25 + 0 + 0 + 0 =
0.5 + 0.125 + 0.062 5 + 0.003 906 25 + 0.000 488 281 25 + 0.000 122 070 312 5 + 0.000 015 258 789 062 5 + 0.000 007 629 394 531 25 + 0.000 001 907 348 632 812 5 + 0.000 000 953 674 316 406 25 =
0.692 042 350 769 042 968 75(10)
= -4 498 220 125 391 865 184 329 006 423 180 574 720
1 - 1111 1000 - 101 1000 1001 0100 1101 1000, a 32 bit single precision IEEE 754 binary floating point representation standard to a decimal number, written in base ten (float) = -4 498 220 125 391 865 184 329 006 423 180 574 720(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.