0.031 415 926 535 897 932 384 626 433 832 795 028 841 971 693 993 740 9 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 0.031 415 926 535 897 932 384 626 433 832 795 028 841 971 693 993 740 9(10) to 64 bit double precision IEEE 754 binary floating point representation standard (1 bit for sign, 11 bits for exponent, 52 bits for mantissa)

What are the steps to convert decimal number
0.031 415 926 535 897 932 384 626 433 832 795 028 841 971 693 993 740 9(10) to 64 bit double precision IEEE 754 binary floating point representation (1 bit for sign, 11 bits for exponent, 52 bits for mantissa)

1. First, convert to binary (in base 2) the integer part: 0.
Divide the number repeatedly by 2.

Keep track of each remainder.

We stop when we get a quotient that is equal to zero.


  • division = quotient + remainder;
  • 0 ÷ 2 = 0 + 0;

2. Construct the base 2 representation of the integer part of the number.

Take all the remainders starting from the bottom of the list constructed above.

0(10) =


0(2)


3. Convert to binary (base 2) the fractional part: 0.031 415 926 535 897 932 384 626 433 832 795 028 841 971 693 993 740 9.

Multiply it repeatedly by 2.


Keep track of each integer part of the results.


Stop when we get a fractional part that is equal to zero.


  • #) multiplying = integer + fractional part;
  • 1) 0.031 415 926 535 897 932 384 626 433 832 795 028 841 971 693 993 740 9 × 2 = 0 + 0.062 831 853 071 795 864 769 252 867 665 590 057 683 943 387 987 481 8;
  • 2) 0.062 831 853 071 795 864 769 252 867 665 590 057 683 943 387 987 481 8 × 2 = 0 + 0.125 663 706 143 591 729 538 505 735 331 180 115 367 886 775 974 963 6;
  • 3) 0.125 663 706 143 591 729 538 505 735 331 180 115 367 886 775 974 963 6 × 2 = 0 + 0.251 327 412 287 183 459 077 011 470 662 360 230 735 773 551 949 927 2;
  • 4) 0.251 327 412 287 183 459 077 011 470 662 360 230 735 773 551 949 927 2 × 2 = 0 + 0.502 654 824 574 366 918 154 022 941 324 720 461 471 547 103 899 854 4;
  • 5) 0.502 654 824 574 366 918 154 022 941 324 720 461 471 547 103 899 854 4 × 2 = 1 + 0.005 309 649 148 733 836 308 045 882 649 440 922 943 094 207 799 708 8;
  • 6) 0.005 309 649 148 733 836 308 045 882 649 440 922 943 094 207 799 708 8 × 2 = 0 + 0.010 619 298 297 467 672 616 091 765 298 881 845 886 188 415 599 417 6;
  • 7) 0.010 619 298 297 467 672 616 091 765 298 881 845 886 188 415 599 417 6 × 2 = 0 + 0.021 238 596 594 935 345 232 183 530 597 763 691 772 376 831 198 835 2;
  • 8) 0.021 238 596 594 935 345 232 183 530 597 763 691 772 376 831 198 835 2 × 2 = 0 + 0.042 477 193 189 870 690 464 367 061 195 527 383 544 753 662 397 670 4;
  • 9) 0.042 477 193 189 870 690 464 367 061 195 527 383 544 753 662 397 670 4 × 2 = 0 + 0.084 954 386 379 741 380 928 734 122 391 054 767 089 507 324 795 340 8;
  • 10) 0.084 954 386 379 741 380 928 734 122 391 054 767 089 507 324 795 340 8 × 2 = 0 + 0.169 908 772 759 482 761 857 468 244 782 109 534 179 014 649 590 681 6;
  • 11) 0.169 908 772 759 482 761 857 468 244 782 109 534 179 014 649 590 681 6 × 2 = 0 + 0.339 817 545 518 965 523 714 936 489 564 219 068 358 029 299 181 363 2;
  • 12) 0.339 817 545 518 965 523 714 936 489 564 219 068 358 029 299 181 363 2 × 2 = 0 + 0.679 635 091 037 931 047 429 872 979 128 438 136 716 058 598 362 726 4;
  • 13) 0.679 635 091 037 931 047 429 872 979 128 438 136 716 058 598 362 726 4 × 2 = 1 + 0.359 270 182 075 862 094 859 745 958 256 876 273 432 117 196 725 452 8;
  • 14) 0.359 270 182 075 862 094 859 745 958 256 876 273 432 117 196 725 452 8 × 2 = 0 + 0.718 540 364 151 724 189 719 491 916 513 752 546 864 234 393 450 905 6;
  • 15) 0.718 540 364 151 724 189 719 491 916 513 752 546 864 234 393 450 905 6 × 2 = 1 + 0.437 080 728 303 448 379 438 983 833 027 505 093 728 468 786 901 811 2;
  • 16) 0.437 080 728 303 448 379 438 983 833 027 505 093 728 468 786 901 811 2 × 2 = 0 + 0.874 161 456 606 896 758 877 967 666 055 010 187 456 937 573 803 622 4;
  • 17) 0.874 161 456 606 896 758 877 967 666 055 010 187 456 937 573 803 622 4 × 2 = 1 + 0.748 322 913 213 793 517 755 935 332 110 020 374 913 875 147 607 244 8;
  • 18) 0.748 322 913 213 793 517 755 935 332 110 020 374 913 875 147 607 244 8 × 2 = 1 + 0.496 645 826 427 587 035 511 870 664 220 040 749 827 750 295 214 489 6;
  • 19) 0.496 645 826 427 587 035 511 870 664 220 040 749 827 750 295 214 489 6 × 2 = 0 + 0.993 291 652 855 174 071 023 741 328 440 081 499 655 500 590 428 979 2;
  • 20) 0.993 291 652 855 174 071 023 741 328 440 081 499 655 500 590 428 979 2 × 2 = 1 + 0.986 583 305 710 348 142 047 482 656 880 162 999 311 001 180 857 958 4;
  • 21) 0.986 583 305 710 348 142 047 482 656 880 162 999 311 001 180 857 958 4 × 2 = 1 + 0.973 166 611 420 696 284 094 965 313 760 325 998 622 002 361 715 916 8;
  • 22) 0.973 166 611 420 696 284 094 965 313 760 325 998 622 002 361 715 916 8 × 2 = 1 + 0.946 333 222 841 392 568 189 930 627 520 651 997 244 004 723 431 833 6;
  • 23) 0.946 333 222 841 392 568 189 930 627 520 651 997 244 004 723 431 833 6 × 2 = 1 + 0.892 666 445 682 785 136 379 861 255 041 303 994 488 009 446 863 667 2;
  • 24) 0.892 666 445 682 785 136 379 861 255 041 303 994 488 009 446 863 667 2 × 2 = 1 + 0.785 332 891 365 570 272 759 722 510 082 607 988 976 018 893 727 334 4;
  • 25) 0.785 332 891 365 570 272 759 722 510 082 607 988 976 018 893 727 334 4 × 2 = 1 + 0.570 665 782 731 140 545 519 445 020 165 215 977 952 037 787 454 668 8;
  • 26) 0.570 665 782 731 140 545 519 445 020 165 215 977 952 037 787 454 668 8 × 2 = 1 + 0.141 331 565 462 281 091 038 890 040 330 431 955 904 075 574 909 337 6;
  • 27) 0.141 331 565 462 281 091 038 890 040 330 431 955 904 075 574 909 337 6 × 2 = 0 + 0.282 663 130 924 562 182 077 780 080 660 863 911 808 151 149 818 675 2;
  • 28) 0.282 663 130 924 562 182 077 780 080 660 863 911 808 151 149 818 675 2 × 2 = 0 + 0.565 326 261 849 124 364 155 560 161 321 727 823 616 302 299 637 350 4;
  • 29) 0.565 326 261 849 124 364 155 560 161 321 727 823 616 302 299 637 350 4 × 2 = 1 + 0.130 652 523 698 248 728 311 120 322 643 455 647 232 604 599 274 700 8;
  • 30) 0.130 652 523 698 248 728 311 120 322 643 455 647 232 604 599 274 700 8 × 2 = 0 + 0.261 305 047 396 497 456 622 240 645 286 911 294 465 209 198 549 401 6;
  • 31) 0.261 305 047 396 497 456 622 240 645 286 911 294 465 209 198 549 401 6 × 2 = 0 + 0.522 610 094 792 994 913 244 481 290 573 822 588 930 418 397 098 803 2;
  • 32) 0.522 610 094 792 994 913 244 481 290 573 822 588 930 418 397 098 803 2 × 2 = 1 + 0.045 220 189 585 989 826 488 962 581 147 645 177 860 836 794 197 606 4;
  • 33) 0.045 220 189 585 989 826 488 962 581 147 645 177 860 836 794 197 606 4 × 2 = 0 + 0.090 440 379 171 979 652 977 925 162 295 290 355 721 673 588 395 212 8;
  • 34) 0.090 440 379 171 979 652 977 925 162 295 290 355 721 673 588 395 212 8 × 2 = 0 + 0.180 880 758 343 959 305 955 850 324 590 580 711 443 347 176 790 425 6;
  • 35) 0.180 880 758 343 959 305 955 850 324 590 580 711 443 347 176 790 425 6 × 2 = 0 + 0.361 761 516 687 918 611 911 700 649 181 161 422 886 694 353 580 851 2;
  • 36) 0.361 761 516 687 918 611 911 700 649 181 161 422 886 694 353 580 851 2 × 2 = 0 + 0.723 523 033 375 837 223 823 401 298 362 322 845 773 388 707 161 702 4;
  • 37) 0.723 523 033 375 837 223 823 401 298 362 322 845 773 388 707 161 702 4 × 2 = 1 + 0.447 046 066 751 674 447 646 802 596 724 645 691 546 777 414 323 404 8;
  • 38) 0.447 046 066 751 674 447 646 802 596 724 645 691 546 777 414 323 404 8 × 2 = 0 + 0.894 092 133 503 348 895 293 605 193 449 291 383 093 554 828 646 809 6;
  • 39) 0.894 092 133 503 348 895 293 605 193 449 291 383 093 554 828 646 809 6 × 2 = 1 + 0.788 184 267 006 697 790 587 210 386 898 582 766 187 109 657 293 619 2;
  • 40) 0.788 184 267 006 697 790 587 210 386 898 582 766 187 109 657 293 619 2 × 2 = 1 + 0.576 368 534 013 395 581 174 420 773 797 165 532 374 219 314 587 238 4;
  • 41) 0.576 368 534 013 395 581 174 420 773 797 165 532 374 219 314 587 238 4 × 2 = 1 + 0.152 737 068 026 791 162 348 841 547 594 331 064 748 438 629 174 476 8;
  • 42) 0.152 737 068 026 791 162 348 841 547 594 331 064 748 438 629 174 476 8 × 2 = 0 + 0.305 474 136 053 582 324 697 683 095 188 662 129 496 877 258 348 953 6;
  • 43) 0.305 474 136 053 582 324 697 683 095 188 662 129 496 877 258 348 953 6 × 2 = 0 + 0.610 948 272 107 164 649 395 366 190 377 324 258 993 754 516 697 907 2;
  • 44) 0.610 948 272 107 164 649 395 366 190 377 324 258 993 754 516 697 907 2 × 2 = 1 + 0.221 896 544 214 329 298 790 732 380 754 648 517 987 509 033 395 814 4;
  • 45) 0.221 896 544 214 329 298 790 732 380 754 648 517 987 509 033 395 814 4 × 2 = 0 + 0.443 793 088 428 658 597 581 464 761 509 297 035 975 018 066 791 628 8;
  • 46) 0.443 793 088 428 658 597 581 464 761 509 297 035 975 018 066 791 628 8 × 2 = 0 + 0.887 586 176 857 317 195 162 929 523 018 594 071 950 036 133 583 257 6;
  • 47) 0.887 586 176 857 317 195 162 929 523 018 594 071 950 036 133 583 257 6 × 2 = 1 + 0.775 172 353 714 634 390 325 859 046 037 188 143 900 072 267 166 515 2;
  • 48) 0.775 172 353 714 634 390 325 859 046 037 188 143 900 072 267 166 515 2 × 2 = 1 + 0.550 344 707 429 268 780 651 718 092 074 376 287 800 144 534 333 030 4;
  • 49) 0.550 344 707 429 268 780 651 718 092 074 376 287 800 144 534 333 030 4 × 2 = 1 + 0.100 689 414 858 537 561 303 436 184 148 752 575 600 289 068 666 060 8;
  • 50) 0.100 689 414 858 537 561 303 436 184 148 752 575 600 289 068 666 060 8 × 2 = 0 + 0.201 378 829 717 075 122 606 872 368 297 505 151 200 578 137 332 121 6;
  • 51) 0.201 378 829 717 075 122 606 872 368 297 505 151 200 578 137 332 121 6 × 2 = 0 + 0.402 757 659 434 150 245 213 744 736 595 010 302 401 156 274 664 243 2;
  • 52) 0.402 757 659 434 150 245 213 744 736 595 010 302 401 156 274 664 243 2 × 2 = 0 + 0.805 515 318 868 300 490 427 489 473 190 020 604 802 312 549 328 486 4;
  • 53) 0.805 515 318 868 300 490 427 489 473 190 020 604 802 312 549 328 486 4 × 2 = 1 + 0.611 030 637 736 600 980 854 978 946 380 041 209 604 625 098 656 972 8;
  • 54) 0.611 030 637 736 600 980 854 978 946 380 041 209 604 625 098 656 972 8 × 2 = 1 + 0.222 061 275 473 201 961 709 957 892 760 082 419 209 250 197 313 945 6;
  • 55) 0.222 061 275 473 201 961 709 957 892 760 082 419 209 250 197 313 945 6 × 2 = 0 + 0.444 122 550 946 403 923 419 915 785 520 164 838 418 500 394 627 891 2;
  • 56) 0.444 122 550 946 403 923 419 915 785 520 164 838 418 500 394 627 891 2 × 2 = 0 + 0.888 245 101 892 807 846 839 831 571 040 329 676 837 000 789 255 782 4;
  • 57) 0.888 245 101 892 807 846 839 831 571 040 329 676 837 000 789 255 782 4 × 2 = 1 + 0.776 490 203 785 615 693 679 663 142 080 659 353 674 001 578 511 564 8;

We didn't get any fractional part that was equal to zero. But we had enough iterations (over Mantissa limit) and at least one integer that was different from zero => FULL STOP (Losing precision - the converted number we get in the end will be just a very good approximation of the initial one).


4. Construct the base 2 representation of the fractional part of the number.

Take all the integer parts of the multiplying operations, starting from the top of the constructed list above:


0.031 415 926 535 897 932 384 626 433 832 795 028 841 971 693 993 740 9(10) =


0.0000 1000 0000 1010 1101 1111 1100 1001 0000 1011 1001 0011 1000 1100 1(2)

5. Positive number before normalization:

0.031 415 926 535 897 932 384 626 433 832 795 028 841 971 693 993 740 9(10) =


0.0000 1000 0000 1010 1101 1111 1100 1001 0000 1011 1001 0011 1000 1100 1(2)

6. Normalize the binary representation of the number.

Shift the decimal mark 5 positions to the right, so that only one non zero digit remains to the left of it:


0.031 415 926 535 897 932 384 626 433 832 795 028 841 971 693 993 740 9(10) =


0.0000 1000 0000 1010 1101 1111 1100 1001 0000 1011 1001 0011 1000 1100 1(2) =


0.0000 1000 0000 1010 1101 1111 1100 1001 0000 1011 1001 0011 1000 1100 1(2) × 20 =


1.0000 0001 0101 1011 1111 1001 0010 0001 0111 0010 0111 0001 1001(2) × 2-5


7. Up to this moment, there are the following elements that would feed into the 64 bit double precision IEEE 754 binary floating point representation:

Sign 0 (a positive number)


Exponent (unadjusted): -5


Mantissa (not normalized):
1.0000 0001 0101 1011 1111 1001 0010 0001 0111 0010 0111 0001 1001


8. Adjust the exponent.

Use the 11 bit excess/bias notation:


Exponent (adjusted) =


Exponent (unadjusted) + 2(11-1) - 1 =


-5 + 2(11-1) - 1 =


(-5 + 1 023)(10) =


1 018(10)


9. Convert the adjusted exponent from the decimal (base 10) to 11 bit binary.

Use the same technique of repeatedly dividing by 2:


  • division = quotient + remainder;
  • 1 018 ÷ 2 = 509 + 0;
  • 509 ÷ 2 = 254 + 1;
  • 254 ÷ 2 = 127 + 0;
  • 127 ÷ 2 = 63 + 1;
  • 63 ÷ 2 = 31 + 1;
  • 31 ÷ 2 = 15 + 1;
  • 15 ÷ 2 = 7 + 1;
  • 7 ÷ 2 = 3 + 1;
  • 3 ÷ 2 = 1 + 1;
  • 1 ÷ 2 = 0 + 1;

10. Construct the base 2 representation of the adjusted exponent.

Take all the remainders starting from the bottom of the list constructed above.


Exponent (adjusted) =


1018(10) =


011 1111 1010(2)


11. Normalize the mantissa.

a) Remove the leading (the leftmost) bit, since it's allways 1, and the decimal point, if the case.


b) Adjust its length to 52 bits, only if necessary (not the case here).


Mantissa (normalized) =


1. 0000 0001 0101 1011 1111 1001 0010 0001 0111 0010 0111 0001 1001 =


0000 0001 0101 1011 1111 1001 0010 0001 0111 0010 0111 0001 1001


12. The three elements that make up the number's 64 bit double precision IEEE 754 binary floating point representation:

Sign (1 bit) =
0 (a positive number)


Exponent (11 bits) =
011 1111 1010


Mantissa (52 bits) =
0000 0001 0101 1011 1111 1001 0010 0001 0111 0010 0111 0001 1001


Decimal number 0.031 415 926 535 897 932 384 626 433 832 795 028 841 971 693 993 740 9 converted to 64 bit double precision IEEE 754 binary floating point representation:

0 - 011 1111 1010 - 0000 0001 0101 1011 1111 1001 0010 0001 0111 0010 0111 0001 1001


How to convert numbers from the decimal system (base ten) to 64 bit double precision IEEE 754 binary floating point standard

Follow the steps below to convert a base 10 decimal number to 64 bit double precision IEEE 754 binary floating point:

  • 1. If the number to be converted is negative, start with its the positive version.
  • 2. First convert the integer part. Divide repeatedly by 2 the positive representation of the integer number that is to be converted to binary, until we get a quotient that is equal to zero, keeping track of each remainder.
  • 3. Construct the base 2 representation of the positive integer part of the number, by taking all the remainders from the previous operations, starting from the bottom of the list constructed above. Thus, the last remainder of the divisions becomes the first symbol (the leftmost) of the base two number, while the first remainder becomes the last symbol (the rightmost).
  • 4. Then convert the fractional part. Multiply the number repeatedly by 2, until we get a fractional part that is equal to zero, keeping track of each integer part of the results.
  • 5. Construct the base 2 representation of the fractional part of the number, by taking all the integer parts of the multiplying operations, starting from the top of the list constructed above (they should appear in the binary representation, from left to right, in the order they have been calculated).
  • 6. Normalize the binary representation of the number, shifting the decimal mark (the decimal point) "n" positions either to the left, or to the right, so that only one non zero digit remains to the left of the decimal mark.
  • 7. Adjust the exponent in 11 bit excess/bias notation and then convert it from decimal (base 10) to 11 bit binary, by using the same technique of repeatedly dividing by 2, as shown above:
    Exponent (adjusted) = Exponent (unadjusted) + 2(11-1) - 1
  • 8. Normalize mantissa, remove the leading (leftmost) bit, since it's allways '1' (and the decimal mark, if the case) and adjust its length to 52 bits, either by removing the excess bits from the right (losing precision...) or by adding extra bits set on '0' to the right.
  • 9. Sign (it takes 1 bit) is either 1 for a negative or 0 for a positive number.

Example: convert the negative number -31.640 215 from the decimal system (base ten) to 64 bit double precision IEEE 754 binary floating point:

  • 1. Start with the positive version of the number:

    |-31.640 215| = 31.640 215

  • 2. First convert the integer part, 31. Divide it repeatedly by 2, keeping track of each remainder, until we get a quotient that is equal to zero:
    • division = quotient + remainder;
    • 31 ÷ 2 = 15 + 1;
    • 15 ÷ 2 = 7 + 1;
    • 7 ÷ 2 = 3 + 1;
    • 3 ÷ 2 = 1 + 1;
    • 1 ÷ 2 = 0 + 1;
    • We have encountered a quotient that is ZERO => FULL STOP
  • 3. Construct the base 2 representation of the integer part of the number by taking all the remainders of the previous dividing operations, starting from the bottom of the list constructed above:

    31(10) = 1 1111(2)

  • 4. Then, convert the fractional part, 0.640 215. Multiply repeatedly by 2, keeping track of each integer part of the results, until we get a fractional part that is equal to zero:
    • #) multiplying = integer + fractional part;
    • 1) 0.640 215 × 2 = 1 + 0.280 43;
    • 2) 0.280 43 × 2 = 0 + 0.560 86;
    • 3) 0.560 86 × 2 = 1 + 0.121 72;
    • 4) 0.121 72 × 2 = 0 + 0.243 44;
    • 5) 0.243 44 × 2 = 0 + 0.486 88;
    • 6) 0.486 88 × 2 = 0 + 0.973 76;
    • 7) 0.973 76 × 2 = 1 + 0.947 52;
    • 8) 0.947 52 × 2 = 1 + 0.895 04;
    • 9) 0.895 04 × 2 = 1 + 0.790 08;
    • 10) 0.790 08 × 2 = 1 + 0.580 16;
    • 11) 0.580 16 × 2 = 1 + 0.160 32;
    • 12) 0.160 32 × 2 = 0 + 0.320 64;
    • 13) 0.320 64 × 2 = 0 + 0.641 28;
    • 14) 0.641 28 × 2 = 1 + 0.282 56;
    • 15) 0.282 56 × 2 = 0 + 0.565 12;
    • 16) 0.565 12 × 2 = 1 + 0.130 24;
    • 17) 0.130 24 × 2 = 0 + 0.260 48;
    • 18) 0.260 48 × 2 = 0 + 0.520 96;
    • 19) 0.520 96 × 2 = 1 + 0.041 92;
    • 20) 0.041 92 × 2 = 0 + 0.083 84;
    • 21) 0.083 84 × 2 = 0 + 0.167 68;
    • 22) 0.167 68 × 2 = 0 + 0.335 36;
    • 23) 0.335 36 × 2 = 0 + 0.670 72;
    • 24) 0.670 72 × 2 = 1 + 0.341 44;
    • 25) 0.341 44 × 2 = 0 + 0.682 88;
    • 26) 0.682 88 × 2 = 1 + 0.365 76;
    • 27) 0.365 76 × 2 = 0 + 0.731 52;
    • 28) 0.731 52 × 2 = 1 + 0.463 04;
    • 29) 0.463 04 × 2 = 0 + 0.926 08;
    • 30) 0.926 08 × 2 = 1 + 0.852 16;
    • 31) 0.852 16 × 2 = 1 + 0.704 32;
    • 32) 0.704 32 × 2 = 1 + 0.408 64;
    • 33) 0.408 64 × 2 = 0 + 0.817 28;
    • 34) 0.817 28 × 2 = 1 + 0.634 56;
    • 35) 0.634 56 × 2 = 1 + 0.269 12;
    • 36) 0.269 12 × 2 = 0 + 0.538 24;
    • 37) 0.538 24 × 2 = 1 + 0.076 48;
    • 38) 0.076 48 × 2 = 0 + 0.152 96;
    • 39) 0.152 96 × 2 = 0 + 0.305 92;
    • 40) 0.305 92 × 2 = 0 + 0.611 84;
    • 41) 0.611 84 × 2 = 1 + 0.223 68;
    • 42) 0.223 68 × 2 = 0 + 0.447 36;
    • 43) 0.447 36 × 2 = 0 + 0.894 72;
    • 44) 0.894 72 × 2 = 1 + 0.789 44;
    • 45) 0.789 44 × 2 = 1 + 0.578 88;
    • 46) 0.578 88 × 2 = 1 + 0.157 76;
    • 47) 0.157 76 × 2 = 0 + 0.315 52;
    • 48) 0.315 52 × 2 = 0 + 0.631 04;
    • 49) 0.631 04 × 2 = 1 + 0.262 08;
    • 50) 0.262 08 × 2 = 0 + 0.524 16;
    • 51) 0.524 16 × 2 = 1 + 0.048 32;
    • 52) 0.048 32 × 2 = 0 + 0.096 64;
    • 53) 0.096 64 × 2 = 0 + 0.193 28;
    • We didn't get any fractional part that was equal to zero. But we had enough iterations (over Mantissa limit = 52) and at least one integer part that was different from zero => FULL STOP (losing precision...).
  • 5. Construct the base 2 representation of the fractional part of the number, by taking all the integer parts of the previous multiplying operations, starting from the top of the constructed list above:

    0.640 215(10) = 0.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2)

  • 6. Summarizing - the positive number before normalization:

    31.640 215(10) = 1 1111.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2)

  • 7. Normalize the binary representation of the number, shifting the decimal mark 4 positions to the left so that only one non-zero digit stays to the left of the decimal mark:

    31.640 215(10) =
    1 1111.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2) =
    1 1111.1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2) × 20 =
    1.1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0(2) × 24

  • 8. Up to this moment, there are the following elements that would feed into the 64 bit double precision IEEE 754 binary floating point representation:

    Sign: 1 (a negative number)

    Exponent (unadjusted): 4

    Mantissa (not-normalized): 1.1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0

  • 9. Adjust the exponent in 11 bit excess/bias notation and then convert it from decimal (base 10) to 11 bit binary (base 2), by using the same technique of repeatedly dividing it by 2, as shown above:

    Exponent (adjusted) = Exponent (unadjusted) + 2(11-1) - 1 = (4 + 1023)(10) = 1027(10) =
    100 0000 0011(2)

  • 10. Normalize mantissa, remove the leading (leftmost) bit, since it's allways '1' (and the decimal sign) and adjust its length to 52 bits, by removing the excess bits, from the right (losing precision...):

    Mantissa (not-normalized): 1.1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100 1010 0

    Mantissa (normalized): 1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100

  • Conclusion:

    Sign (1 bit) = 1 (a negative number)

    Exponent (8 bits) = 100 0000 0011

    Mantissa (52 bits) = 1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100

  • Number -31.640 215, converted from decimal system (base 10) to 64 bit double precision IEEE 754 binary floating point =
    1 - 100 0000 0011 - 1111 1010 0011 1110 0101 0010 0001 0101 0111 0110 1000 1001 1100