1 - 111 1110 1000 - 0010 1000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001 1010 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard Converted to Decimal
1 - 111 1110 1000 - 0010 1000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001 1010: 64 bit double precision IEEE 754 binary floating point representation standard converted to decimal
What are the steps to convert
1 - 111 1110 1000 - 0010 1000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001 1010, a 64 bit double 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 11 bits contain the exponent:
111 1110 1000
The last 52 bits contain the mantissa:
0010 1000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001 1010
2. Convert the exponent from binary (from base 2) to decimal (in base 10).
The exponent is allways a positive integer.
111 1110 1000(2) =
1 × 210 + 1 × 29 + 1 × 28 + 1 × 27 + 1 × 26 + 1 × 25 + 0 × 24 + 1 × 23 + 0 × 22 + 0 × 21 + 0 × 20 =
1,024 + 512 + 256 + 128 + 64 + 32 + 0 + 8 + 0 + 0 + 0 =
1,024 + 512 + 256 + 128 + 64 + 32 + 8 =
2,024(10)
3. Adjust the exponent.
Subtract the excess bits: 2(11 - 1) - 1 = 1023,
that is due to the 11 bit excess/bias notation.
The exponent, adjusted = 2,024 - 1023 = 1001
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).
0010 1000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001 1010(2) =
0 × 2-1 + 0 × 2-2 + 1 × 2-3 + 0 × 2-4 + 1 × 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 + 0 × 2-17 + 0 × 2-18 + 0 × 2-19 + 0 × 2-20 + 0 × 2-21 + 0 × 2-22 + 0 × 2-23 + 0 × 2-24 + 0 × 2-25 + 0 × 2-26 + 0 × 2-27 + 0 × 2-28 + 0 × 2-29 + 0 × 2-30 + 0 × 2-31 + 0 × 2-32 + 0 × 2-33 + 0 × 2-34 + 0 × 2-35 + 0 × 2-36 + 0 × 2-37 + 0 × 2-38 + 0 × 2-39 + 0 × 2-40 + 0 × 2-41 + 0 × 2-42 + 0 × 2-43 + 0 × 2-44 + 0 × 2-45 + 0 × 2-46 + 0 × 2-47 + 1 × 2-48 + 1 × 2-49 + 0 × 2-50 + 1 × 2-51 + 0 × 2-52 =
0 + 0 + 0.125 + 0 + 0.031 25 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0.000 000 000 000 003 552 713 678 800 500 929 355 621 337 890 625 + 0.000 000 000 000 001 776 356 839 400 250 464 677 810 668 945 312 5 + 0 + 0.000 000 000 000 000 444 089 209 850 062 616 169 452 667 236 328 125 + 0 =
0.125 + 0.031 25 + 0.000 000 000 000 003 552 713 678 800 500 929 355 621 337 890 625 + 0.000 000 000 000 001 776 356 839 400 250 464 677 810 668 945 312 5 + 0.000 000 000 000 000 444 089 209 850 062 616 169 452 667 236 328 125 =
0.156 250 000 000 005 773 159 728 050 814 010 202 884 674 072 265 625(10)
5. Put all the numbers into expression to calculate the double precision floating point decimal value:
(-1)Sign × (1 + Mantissa) × 2(Adjusted exponent) =
(-1)1 × (1 + 0.156 250 000 000 005 773 159 728 050 814 010 202 884 674 072 265 625) × 21001 =
-1.156 250 000 000 005 773 159 728 050 814 010 202 884 674 072 265 625 × 21001 = ...
= -24 778 636 541 182 555 516 739 114 611 063 366 668 032 332 342 417 067 592 985 505 792 683 361 497 482 842 918 917 888 255 756 845 677 204 392 891 426 785 591 586 272 078 786 992 560 079 706 764 977 645 342 431 203 035 698 513 899 296 960 160 252 868 245 297 102 067 259 800 627 577 300 622 330 820 435 194 817 262 732 614 926 542 660 577 728 863 002 635 364 867 517 770 470 240 831 838 059 489 132 544
1 - 111 1110 1000 - 0010 1000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0001 1010, a 64 bit double precision IEEE 754 binary floating point representation standard to a decimal number, written in base ten (double) = -24 778 636 541 182 555 516 739 114 611 063 366 668 032 332 342 417 067 592 985 505 792 683 361 497 482 842 918 917 888 255 756 845 677 204 392 891 426 785 591 586 272 078 786 992 560 079 706 764 977 645 342 431 203 035 698 513 899 296 960 160 252 868 245 297 102 067 259 800 627 577 300 622 330 820 435 194 817 262 732 614 926 542 660 577 728 863 002 635 364 867 517 770 470 240 831 838 059 489 132 544(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.