0.000 020 830 729 321 671 205 134 999 154 509 660 617 319 5 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 0.000 020 830 729 321 671 205 134 999 154 509 660 617 319 5(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
0.000 020 830 729 321 671 205 134 999 154 509 660 617 319 5(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: 0.000 020 830 729 321 671 205 134 999 154 509 660 617 319 5.

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) 0.000 020 830 729 321 671 205 134 999 154 509 660 617 319 5 × 2 = 0 + 0.000 041 661 458 643 342 410 269 998 309 019 321 234 639;
  • 2) 0.000 041 661 458 643 342 410 269 998 309 019 321 234 639 × 2 = 0 + 0.000 083 322 917 286 684 820 539 996 618 038 642 469 278;
  • 3) 0.000 083 322 917 286 684 820 539 996 618 038 642 469 278 × 2 = 0 + 0.000 166 645 834 573 369 641 079 993 236 077 284 938 556;
  • 4) 0.000 166 645 834 573 369 641 079 993 236 077 284 938 556 × 2 = 0 + 0.000 333 291 669 146 739 282 159 986 472 154 569 877 112;
  • 5) 0.000 333 291 669 146 739 282 159 986 472 154 569 877 112 × 2 = 0 + 0.000 666 583 338 293 478 564 319 972 944 309 139 754 224;
  • 6) 0.000 666 583 338 293 478 564 319 972 944 309 139 754 224 × 2 = 0 + 0.001 333 166 676 586 957 128 639 945 888 618 279 508 448;
  • 7) 0.001 333 166 676 586 957 128 639 945 888 618 279 508 448 × 2 = 0 + 0.002 666 333 353 173 914 257 279 891 777 236 559 016 896;
  • 8) 0.002 666 333 353 173 914 257 279 891 777 236 559 016 896 × 2 = 0 + 0.005 332 666 706 347 828 514 559 783 554 473 118 033 792;
  • 9) 0.005 332 666 706 347 828 514 559 783 554 473 118 033 792 × 2 = 0 + 0.010 665 333 412 695 657 029 119 567 108 946 236 067 584;
  • 10) 0.010 665 333 412 695 657 029 119 567 108 946 236 067 584 × 2 = 0 + 0.021 330 666 825 391 314 058 239 134 217 892 472 135 168;
  • 11) 0.021 330 666 825 391 314 058 239 134 217 892 472 135 168 × 2 = 0 + 0.042 661 333 650 782 628 116 478 268 435 784 944 270 336;
  • 12) 0.042 661 333 650 782 628 116 478 268 435 784 944 270 336 × 2 = 0 + 0.085 322 667 301 565 256 232 956 536 871 569 888 540 672;
  • 13) 0.085 322 667 301 565 256 232 956 536 871 569 888 540 672 × 2 = 0 + 0.170 645 334 603 130 512 465 913 073 743 139 777 081 344;
  • 14) 0.170 645 334 603 130 512 465 913 073 743 139 777 081 344 × 2 = 0 + 0.341 290 669 206 261 024 931 826 147 486 279 554 162 688;
  • 15) 0.341 290 669 206 261 024 931 826 147 486 279 554 162 688 × 2 = 0 + 0.682 581 338 412 522 049 863 652 294 972 559 108 325 376;
  • 16) 0.682 581 338 412 522 049 863 652 294 972 559 108 325 376 × 2 = 1 + 0.365 162 676 825 044 099 727 304 589 945 118 216 650 752;
  • 17) 0.365 162 676 825 044 099 727 304 589 945 118 216 650 752 × 2 = 0 + 0.730 325 353 650 088 199 454 609 179 890 236 433 301 504;
  • 18) 0.730 325 353 650 088 199 454 609 179 890 236 433 301 504 × 2 = 1 + 0.460 650 707 300 176 398 909 218 359 780 472 866 603 008;
  • 19) 0.460 650 707 300 176 398 909 218 359 780 472 866 603 008 × 2 = 0 + 0.921 301 414 600 352 797 818 436 719 560 945 733 206 016;
  • 20) 0.921 301 414 600 352 797 818 436 719 560 945 733 206 016 × 2 = 1 + 0.842 602 829 200 705 595 636 873 439 121 891 466 412 032;
  • 21) 0.842 602 829 200 705 595 636 873 439 121 891 466 412 032 × 2 = 1 + 0.685 205 658 401 411 191 273 746 878 243 782 932 824 064;
  • 22) 0.685 205 658 401 411 191 273 746 878 243 782 932 824 064 × 2 = 1 + 0.370 411 316 802 822 382 547 493 756 487 565 865 648 128;
  • 23) 0.370 411 316 802 822 382 547 493 756 487 565 865 648 128 × 2 = 0 + 0.740 822 633 605 644 765 094 987 512 975 131 731 296 256;
  • 24) 0.740 822 633 605 644 765 094 987 512 975 131 731 296 256 × 2 = 1 + 0.481 645 267 211 289 530 189 975 025 950 263 462 592 512;
  • 25) 0.481 645 267 211 289 530 189 975 025 950 263 462 592 512 × 2 = 0 + 0.963 290 534 422 579 060 379 950 051 900 526 925 185 024;
  • 26) 0.963 290 534 422 579 060 379 950 051 900 526 925 185 024 × 2 = 1 + 0.926 581 068 845 158 120 759 900 103 801 053 850 370 048;
  • 27) 0.926 581 068 845 158 120 759 900 103 801 053 850 370 048 × 2 = 1 + 0.853 162 137 690 316 241 519 800 207 602 107 700 740 096;
  • 28) 0.853 162 137 690 316 241 519 800 207 602 107 700 740 096 × 2 = 1 + 0.706 324 275 380 632 483 039 600 415 204 215 401 480 192;
  • 29) 0.706 324 275 380 632 483 039 600 415 204 215 401 480 192 × 2 = 1 + 0.412 648 550 761 264 966 079 200 830 408 430 802 960 384;
  • 30) 0.412 648 550 761 264 966 079 200 830 408 430 802 960 384 × 2 = 0 + 0.825 297 101 522 529 932 158 401 660 816 861 605 920 768;
  • 31) 0.825 297 101 522 529 932 158 401 660 816 861 605 920 768 × 2 = 1 + 0.650 594 203 045 059 864 316 803 321 633 723 211 841 536;
  • 32) 0.650 594 203 045 059 864 316 803 321 633 723 211 841 536 × 2 = 1 + 0.301 188 406 090 119 728 633 606 643 267 446 423 683 072;
  • 33) 0.301 188 406 090 119 728 633 606 643 267 446 423 683 072 × 2 = 0 + 0.602 376 812 180 239 457 267 213 286 534 892 847 366 144;
  • 34) 0.602 376 812 180 239 457 267 213 286 534 892 847 366 144 × 2 = 1 + 0.204 753 624 360 478 914 534 426 573 069 785 694 732 288;
  • 35) 0.204 753 624 360 478 914 534 426 573 069 785 694 732 288 × 2 = 0 + 0.409 507 248 720 957 829 068 853 146 139 571 389 464 576;
  • 36) 0.409 507 248 720 957 829 068 853 146 139 571 389 464 576 × 2 = 0 + 0.819 014 497 441 915 658 137 706 292 279 142 778 929 152;
  • 37) 0.819 014 497 441 915 658 137 706 292 279 142 778 929 152 × 2 = 1 + 0.638 028 994 883 831 316 275 412 584 558 285 557 858 304;
  • 38) 0.638 028 994 883 831 316 275 412 584 558 285 557 858 304 × 2 = 1 + 0.276 057 989 767 662 632 550 825 169 116 571 115 716 608;
  • 39) 0.276 057 989 767 662 632 550 825 169 116 571 115 716 608 × 2 = 0 + 0.552 115 979 535 325 265 101 650 338 233 142 231 433 216;
  • 40) 0.552 115 979 535 325 265 101 650 338 233 142 231 433 216 × 2 = 1 + 0.104 231 959 070 650 530 203 300 676 466 284 462 866 432;
  • 41) 0.104 231 959 070 650 530 203 300 676 466 284 462 866 432 × 2 = 0 + 0.208 463 918 141 301 060 406 601 352 932 568 925 732 864;
  • 42) 0.208 463 918 141 301 060 406 601 352 932 568 925 732 864 × 2 = 0 + 0.416 927 836 282 602 120 813 202 705 865 137 851 465 728;
  • 43) 0.416 927 836 282 602 120 813 202 705 865 137 851 465 728 × 2 = 0 + 0.833 855 672 565 204 241 626 405 411 730 275 702 931 456;
  • 44) 0.833 855 672 565 204 241 626 405 411 730 275 702 931 456 × 2 = 1 + 0.667 711 345 130 408 483 252 810 823 460 551 405 862 912;
  • 45) 0.667 711 345 130 408 483 252 810 823 460 551 405 862 912 × 2 = 1 + 0.335 422 690 260 816 966 505 621 646 921 102 811 725 824;
  • 46) 0.335 422 690 260 816 966 505 621 646 921 102 811 725 824 × 2 = 0 + 0.670 845 380 521 633 933 011 243 293 842 205 623 451 648;
  • 47) 0.670 845 380 521 633 933 011 243 293 842 205 623 451 648 × 2 = 1 + 0.341 690 761 043 267 866 022 486 587 684 411 246 903 296;
  • 48) 0.341 690 761 043 267 866 022 486 587 684 411 246 903 296 × 2 = 0 + 0.683 381 522 086 535 732 044 973 175 368 822 493 806 592;
  • 49) 0.683 381 522 086 535 732 044 973 175 368 822 493 806 592 × 2 = 1 + 0.366 763 044 173 071 464 089 946 350 737 644 987 613 184;
  • 50) 0.366 763 044 173 071 464 089 946 350 737 644 987 613 184 × 2 = 0 + 0.733 526 088 346 142 928 179 892 701 475 289 975 226 368;
  • 51) 0.733 526 088 346 142 928 179 892 701 475 289 975 226 368 × 2 = 1 + 0.467 052 176 692 285 856 359 785 402 950 579 950 452 736;
  • 52) 0.467 052 176 692 285 856 359 785 402 950 579 950 452 736 × 2 = 0 + 0.934 104 353 384 571 712 719 570 805 901 159 900 905 472;
  • 53) 0.934 104 353 384 571 712 719 570 805 901 159 900 905 472 × 2 = 1 + 0.868 208 706 769 143 425 439 141 611 802 319 801 810 944;
  • 54) 0.868 208 706 769 143 425 439 141 611 802 319 801 810 944 × 2 = 1 + 0.736 417 413 538 286 850 878 283 223 604 639 603 621 888;
  • 55) 0.736 417 413 538 286 850 878 283 223 604 639 603 621 888 × 2 = 1 + 0.472 834 827 076 573 701 756 566 447 209 279 207 243 776;
  • 56) 0.472 834 827 076 573 701 756 566 447 209 279 207 243 776 × 2 = 0 + 0.945 669 654 153 147 403 513 132 894 418 558 414 487 552;
  • 57) 0.945 669 654 153 147 403 513 132 894 418 558 414 487 552 × 2 = 1 + 0.891 339 308 306 294 807 026 265 788 837 116 828 975 104;
  • 58) 0.891 339 308 306 294 807 026 265 788 837 116 828 975 104 × 2 = 1 + 0.782 678 616 612 589 614 052 531 577 674 233 657 950 208;
  • 59) 0.782 678 616 612 589 614 052 531 577 674 233 657 950 208 × 2 = 1 + 0.565 357 233 225 179 228 105 063 155 348 467 315 900 416;
  • 60) 0.565 357 233 225 179 228 105 063 155 348 467 315 900 416 × 2 = 1 + 0.130 714 466 450 358 456 210 126 310 696 934 631 800 832;
  • 61) 0.130 714 466 450 358 456 210 126 310 696 934 631 800 832 × 2 = 0 + 0.261 428 932 900 716 912 420 252 621 393 869 263 601 664;
  • 62) 0.261 428 932 900 716 912 420 252 621 393 869 263 601 664 × 2 = 0 + 0.522 857 865 801 433 824 840 505 242 787 738 527 203 328;
  • 63) 0.522 857 865 801 433 824 840 505 242 787 738 527 203 328 × 2 = 1 + 0.045 715 731 602 867 649 681 010 485 575 477 054 406 656;
  • 64) 0.045 715 731 602 867 649 681 010 485 575 477 054 406 656 × 2 = 0 + 0.091 431 463 205 735 299 362 020 971 150 954 108 813 312;
  • 65) 0.091 431 463 205 735 299 362 020 971 150 954 108 813 312 × 2 = 0 + 0.182 862 926 411 470 598 724 041 942 301 908 217 626 624;
  • 66) 0.182 862 926 411 470 598 724 041 942 301 908 217 626 624 × 2 = 0 + 0.365 725 852 822 941 197 448 083 884 603 816 435 253 248;
  • 67) 0.365 725 852 822 941 197 448 083 884 603 816 435 253 248 × 2 = 0 + 0.731 451 705 645 882 394 896 167 769 207 632 870 506 496;
  • 68) 0.731 451 705 645 882 394 896 167 769 207 632 870 506 496 × 2 = 1 + 0.462 903 411 291 764 789 792 335 538 415 265 741 012 992;

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:


0.000 020 830 729 321 671 205 134 999 154 509 660 617 319 5(10) =


0.0000 0000 0000 0001 0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001(2)

5. Positive number before normalization:

0.000 020 830 729 321 671 205 134 999 154 509 660 617 319 5(10) =


0.0000 0000 0000 0001 0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001(2)

6. Normalize the binary representation of the number.

Shift the decimal mark 16 positions to the right, so that only one non zero digit remains to the left of it:


0.000 020 830 729 321 671 205 134 999 154 509 660 617 319 5(10) =


0.0000 0000 0000 0001 0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001(2) =


0.0000 0000 0000 0001 0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001(2) × 20 =


1.0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001(2) × 2-16


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): -16


Mantissa (not normalized):
1.0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001


8. Adjust the exponent.

Use the 11 bit excess/bias notation:


Exponent (adjusted) =


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


-16 + 2(11-1) - 1 =


(-16 + 1 023)(10) =


1 007(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;
  • 1 007 ÷ 2 = 503 + 1;
  • 503 ÷ 2 = 251 + 1;
  • 251 ÷ 2 = 125 + 1;
  • 125 ÷ 2 = 62 + 1;
  • 62 ÷ 2 = 31 + 0;
  • 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) =


1007(10) =


011 1110 1111(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. 0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001 =


0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001


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 1110 1111


Mantissa (52 bits) =
0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001


Decimal number 0.000 020 830 729 321 671 205 134 999 154 509 660 617 319 5 converted to 64 bit double precision IEEE 754 binary floating point representation:

0 - 011 1110 1111 - 0101 1101 0111 1011 0100 1101 0001 1010 1010 1110 1111 0010 0001


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