2.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 959 574 966 967 627 724 076 630 353 541 9 Converted to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard

Convert decimal 2.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 959 574 966 967 627 724 076 630 353 541 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
2.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 959 574 966 967 627 724 076 630 353 541 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: 2.
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;
  • 2 ÷ 2 = 1 + 0;
  • 1 ÷ 2 = 0 + 1;

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.

2(10) =

10(2)


3. Convert to binary (base 2) the fractional part: 0.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 959 574 966 967 627 724 076 630 353 541 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) 0.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 959 574 966 967 627 724 076 630 353 541 9 × 2 = 1 + 0.436 563 656 918 090 470 720 574 942 705 324 995 514 494 187 399 919 149 933 935 255 448 153 260 707 083 8;
  • 2) 0.436 563 656 918 090 470 720 574 942 705 324 995 514 494 187 399 919 149 933 935 255 448 153 260 707 083 8 × 2 = 0 + 0.873 127 313 836 180 941 441 149 885 410 649 991 028 988 374 799 838 299 867 870 510 896 306 521 414 167 6;
  • 3) 0.873 127 313 836 180 941 441 149 885 410 649 991 028 988 374 799 838 299 867 870 510 896 306 521 414 167 6 × 2 = 1 + 0.746 254 627 672 361 882 882 299 770 821 299 982 057 976 749 599 676 599 735 741 021 792 613 042 828 335 2;
  • 4) 0.746 254 627 672 361 882 882 299 770 821 299 982 057 976 749 599 676 599 735 741 021 792 613 042 828 335 2 × 2 = 1 + 0.492 509 255 344 723 765 764 599 541 642 599 964 115 953 499 199 353 199 471 482 043 585 226 085 656 670 4;
  • 5) 0.492 509 255 344 723 765 764 599 541 642 599 964 115 953 499 199 353 199 471 482 043 585 226 085 656 670 4 × 2 = 0 + 0.985 018 510 689 447 531 529 199 083 285 199 928 231 906 998 398 706 398 942 964 087 170 452 171 313 340 8;
  • 6) 0.985 018 510 689 447 531 529 199 083 285 199 928 231 906 998 398 706 398 942 964 087 170 452 171 313 340 8 × 2 = 1 + 0.970 037 021 378 895 063 058 398 166 570 399 856 463 813 996 797 412 797 885 928 174 340 904 342 626 681 6;
  • 7) 0.970 037 021 378 895 063 058 398 166 570 399 856 463 813 996 797 412 797 885 928 174 340 904 342 626 681 6 × 2 = 1 + 0.940 074 042 757 790 126 116 796 333 140 799 712 927 627 993 594 825 595 771 856 348 681 808 685 253 363 2;
  • 8) 0.940 074 042 757 790 126 116 796 333 140 799 712 927 627 993 594 825 595 771 856 348 681 808 685 253 363 2 × 2 = 1 + 0.880 148 085 515 580 252 233 592 666 281 599 425 855 255 987 189 651 191 543 712 697 363 617 370 506 726 4;
  • 9) 0.880 148 085 515 580 252 233 592 666 281 599 425 855 255 987 189 651 191 543 712 697 363 617 370 506 726 4 × 2 = 1 + 0.760 296 171 031 160 504 467 185 332 563 198 851 710 511 974 379 302 383 087 425 394 727 234 741 013 452 8;
  • 10) 0.760 296 171 031 160 504 467 185 332 563 198 851 710 511 974 379 302 383 087 425 394 727 234 741 013 452 8 × 2 = 1 + 0.520 592 342 062 321 008 934 370 665 126 397 703 421 023 948 758 604 766 174 850 789 454 469 482 026 905 6;
  • 11) 0.520 592 342 062 321 008 934 370 665 126 397 703 421 023 948 758 604 766 174 850 789 454 469 482 026 905 6 × 2 = 1 + 0.041 184 684 124 642 017 868 741 330 252 795 406 842 047 897 517 209 532 349 701 578 908 938 964 053 811 2;
  • 12) 0.041 184 684 124 642 017 868 741 330 252 795 406 842 047 897 517 209 532 349 701 578 908 938 964 053 811 2 × 2 = 0 + 0.082 369 368 249 284 035 737 482 660 505 590 813 684 095 795 034 419 064 699 403 157 817 877 928 107 622 4;
  • 13) 0.082 369 368 249 284 035 737 482 660 505 590 813 684 095 795 034 419 064 699 403 157 817 877 928 107 622 4 × 2 = 0 + 0.164 738 736 498 568 071 474 965 321 011 181 627 368 191 590 068 838 129 398 806 315 635 755 856 215 244 8;
  • 14) 0.164 738 736 498 568 071 474 965 321 011 181 627 368 191 590 068 838 129 398 806 315 635 755 856 215 244 8 × 2 = 0 + 0.329 477 472 997 136 142 949 930 642 022 363 254 736 383 180 137 676 258 797 612 631 271 511 712 430 489 6;
  • 15) 0.329 477 472 997 136 142 949 930 642 022 363 254 736 383 180 137 676 258 797 612 631 271 511 712 430 489 6 × 2 = 0 + 0.658 954 945 994 272 285 899 861 284 044 726 509 472 766 360 275 352 517 595 225 262 543 023 424 860 979 2;
  • 16) 0.658 954 945 994 272 285 899 861 284 044 726 509 472 766 360 275 352 517 595 225 262 543 023 424 860 979 2 × 2 = 1 + 0.317 909 891 988 544 571 799 722 568 089 453 018 945 532 720 550 705 035 190 450 525 086 046 849 721 958 4;
  • 17) 0.317 909 891 988 544 571 799 722 568 089 453 018 945 532 720 550 705 035 190 450 525 086 046 849 721 958 4 × 2 = 0 + 0.635 819 783 977 089 143 599 445 136 178 906 037 891 065 441 101 410 070 380 901 050 172 093 699 443 916 8;
  • 18) 0.635 819 783 977 089 143 599 445 136 178 906 037 891 065 441 101 410 070 380 901 050 172 093 699 443 916 8 × 2 = 1 + 0.271 639 567 954 178 287 198 890 272 357 812 075 782 130 882 202 820 140 761 802 100 344 187 398 887 833 6;
  • 19) 0.271 639 567 954 178 287 198 890 272 357 812 075 782 130 882 202 820 140 761 802 100 344 187 398 887 833 6 × 2 = 0 + 0.543 279 135 908 356 574 397 780 544 715 624 151 564 261 764 405 640 281 523 604 200 688 374 797 775 667 2;
  • 20) 0.543 279 135 908 356 574 397 780 544 715 624 151 564 261 764 405 640 281 523 604 200 688 374 797 775 667 2 × 2 = 1 + 0.086 558 271 816 713 148 795 561 089 431 248 303 128 523 528 811 280 563 047 208 401 376 749 595 551 334 4;
  • 21) 0.086 558 271 816 713 148 795 561 089 431 248 303 128 523 528 811 280 563 047 208 401 376 749 595 551 334 4 × 2 = 0 + 0.173 116 543 633 426 297 591 122 178 862 496 606 257 047 057 622 561 126 094 416 802 753 499 191 102 668 8;
  • 22) 0.173 116 543 633 426 297 591 122 178 862 496 606 257 047 057 622 561 126 094 416 802 753 499 191 102 668 8 × 2 = 0 + 0.346 233 087 266 852 595 182 244 357 724 993 212 514 094 115 245 122 252 188 833 605 506 998 382 205 337 6;
  • 23) 0.346 233 087 266 852 595 182 244 357 724 993 212 514 094 115 245 122 252 188 833 605 506 998 382 205 337 6 × 2 = 0 + 0.692 466 174 533 705 190 364 488 715 449 986 425 028 188 230 490 244 504 377 667 211 013 996 764 410 675 2;
  • 24) 0.692 466 174 533 705 190 364 488 715 449 986 425 028 188 230 490 244 504 377 667 211 013 996 764 410 675 2 × 2 = 1 + 0.384 932 349 067 410 380 728 977 430 899 972 850 056 376 460 980 489 008 755 334 422 027 993 528 821 350 4;
  • 25) 0.384 932 349 067 410 380 728 977 430 899 972 850 056 376 460 980 489 008 755 334 422 027 993 528 821 350 4 × 2 = 0 + 0.769 864 698 134 820 761 457 954 861 799 945 700 112 752 921 960 978 017 510 668 844 055 987 057 642 700 8;
  • 26) 0.769 864 698 134 820 761 457 954 861 799 945 700 112 752 921 960 978 017 510 668 844 055 987 057 642 700 8 × 2 = 1 + 0.539 729 396 269 641 522 915 909 723 599 891 400 225 505 843 921 956 035 021 337 688 111 974 115 285 401 6;
  • 27) 0.539 729 396 269 641 522 915 909 723 599 891 400 225 505 843 921 956 035 021 337 688 111 974 115 285 401 6 × 2 = 1 + 0.079 458 792 539 283 045 831 819 447 199 782 800 451 011 687 843 912 070 042 675 376 223 948 230 570 803 2;
  • 28) 0.079 458 792 539 283 045 831 819 447 199 782 800 451 011 687 843 912 070 042 675 376 223 948 230 570 803 2 × 2 = 0 + 0.158 917 585 078 566 091 663 638 894 399 565 600 902 023 375 687 824 140 085 350 752 447 896 461 141 606 4;
  • 29) 0.158 917 585 078 566 091 663 638 894 399 565 600 902 023 375 687 824 140 085 350 752 447 896 461 141 606 4 × 2 = 0 + 0.317 835 170 157 132 183 327 277 788 799 131 201 804 046 751 375 648 280 170 701 504 895 792 922 283 212 8;
  • 30) 0.317 835 170 157 132 183 327 277 788 799 131 201 804 046 751 375 648 280 170 701 504 895 792 922 283 212 8 × 2 = 0 + 0.635 670 340 314 264 366 654 555 577 598 262 403 608 093 502 751 296 560 341 403 009 791 585 844 566 425 6;
  • 31) 0.635 670 340 314 264 366 654 555 577 598 262 403 608 093 502 751 296 560 341 403 009 791 585 844 566 425 6 × 2 = 1 + 0.271 340 680 628 528 733 309 111 155 196 524 807 216 187 005 502 593 120 682 806 019 583 171 689 132 851 2;
  • 32) 0.271 340 680 628 528 733 309 111 155 196 524 807 216 187 005 502 593 120 682 806 019 583 171 689 132 851 2 × 2 = 0 + 0.542 681 361 257 057 466 618 222 310 393 049 614 432 374 011 005 186 241 365 612 039 166 343 378 265 702 4;
  • 33) 0.542 681 361 257 057 466 618 222 310 393 049 614 432 374 011 005 186 241 365 612 039 166 343 378 265 702 4 × 2 = 1 + 0.085 362 722 514 114 933 236 444 620 786 099 228 864 748 022 010 372 482 731 224 078 332 686 756 531 404 8;
  • 34) 0.085 362 722 514 114 933 236 444 620 786 099 228 864 748 022 010 372 482 731 224 078 332 686 756 531 404 8 × 2 = 0 + 0.170 725 445 028 229 866 472 889 241 572 198 457 729 496 044 020 744 965 462 448 156 665 373 513 062 809 6;
  • 35) 0.170 725 445 028 229 866 472 889 241 572 198 457 729 496 044 020 744 965 462 448 156 665 373 513 062 809 6 × 2 = 0 + 0.341 450 890 056 459 732 945 778 483 144 396 915 458 992 088 041 489 930 924 896 313 330 747 026 125 619 2;
  • 36) 0.341 450 890 056 459 732 945 778 483 144 396 915 458 992 088 041 489 930 924 896 313 330 747 026 125 619 2 × 2 = 0 + 0.682 901 780 112 919 465 891 556 966 288 793 830 917 984 176 082 979 861 849 792 626 661 494 052 251 238 4;
  • 37) 0.682 901 780 112 919 465 891 556 966 288 793 830 917 984 176 082 979 861 849 792 626 661 494 052 251 238 4 × 2 = 1 + 0.365 803 560 225 838 931 783 113 932 577 587 661 835 968 352 165 959 723 699 585 253 322 988 104 502 476 8;
  • 38) 0.365 803 560 225 838 931 783 113 932 577 587 661 835 968 352 165 959 723 699 585 253 322 988 104 502 476 8 × 2 = 0 + 0.731 607 120 451 677 863 566 227 865 155 175 323 671 936 704 331 919 447 399 170 506 645 976 209 004 953 6;
  • 39) 0.731 607 120 451 677 863 566 227 865 155 175 323 671 936 704 331 919 447 399 170 506 645 976 209 004 953 6 × 2 = 1 + 0.463 214 240 903 355 727 132 455 730 310 350 647 343 873 408 663 838 894 798 341 013 291 952 418 009 907 2;
  • 40) 0.463 214 240 903 355 727 132 455 730 310 350 647 343 873 408 663 838 894 798 341 013 291 952 418 009 907 2 × 2 = 0 + 0.926 428 481 806 711 454 264 911 460 620 701 294 687 746 817 327 677 789 596 682 026 583 904 836 019 814 4;
  • 41) 0.926 428 481 806 711 454 264 911 460 620 701 294 687 746 817 327 677 789 596 682 026 583 904 836 019 814 4 × 2 = 1 + 0.852 856 963 613 422 908 529 822 921 241 402 589 375 493 634 655 355 579 193 364 053 167 809 672 039 628 8;
  • 42) 0.852 856 963 613 422 908 529 822 921 241 402 589 375 493 634 655 355 579 193 364 053 167 809 672 039 628 8 × 2 = 1 + 0.705 713 927 226 845 817 059 645 842 482 805 178 750 987 269 310 711 158 386 728 106 335 619 344 079 257 6;
  • 43) 0.705 713 927 226 845 817 059 645 842 482 805 178 750 987 269 310 711 158 386 728 106 335 619 344 079 257 6 × 2 = 1 + 0.411 427 854 453 691 634 119 291 684 965 610 357 501 974 538 621 422 316 773 456 212 671 238 688 158 515 2;
  • 44) 0.411 427 854 453 691 634 119 291 684 965 610 357 501 974 538 621 422 316 773 456 212 671 238 688 158 515 2 × 2 = 0 + 0.822 855 708 907 383 268 238 583 369 931 220 715 003 949 077 242 844 633 546 912 425 342 477 376 317 030 4;
  • 45) 0.822 855 708 907 383 268 238 583 369 931 220 715 003 949 077 242 844 633 546 912 425 342 477 376 317 030 4 × 2 = 1 + 0.645 711 417 814 766 536 477 166 739 862 441 430 007 898 154 485 689 267 093 824 850 684 954 752 634 060 8;
  • 46) 0.645 711 417 814 766 536 477 166 739 862 441 430 007 898 154 485 689 267 093 824 850 684 954 752 634 060 8 × 2 = 1 + 0.291 422 835 629 533 072 954 333 479 724 882 860 015 796 308 971 378 534 187 649 701 369 909 505 268 121 6;
  • 47) 0.291 422 835 629 533 072 954 333 479 724 882 860 015 796 308 971 378 534 187 649 701 369 909 505 268 121 6 × 2 = 0 + 0.582 845 671 259 066 145 908 666 959 449 765 720 031 592 617 942 757 068 375 299 402 739 819 010 536 243 2;
  • 48) 0.582 845 671 259 066 145 908 666 959 449 765 720 031 592 617 942 757 068 375 299 402 739 819 010 536 243 2 × 2 = 1 + 0.165 691 342 518 132 291 817 333 918 899 531 440 063 185 235 885 514 136 750 598 805 479 638 021 072 486 4;
  • 49) 0.165 691 342 518 132 291 817 333 918 899 531 440 063 185 235 885 514 136 750 598 805 479 638 021 072 486 4 × 2 = 0 + 0.331 382 685 036 264 583 634 667 837 799 062 880 126 370 471 771 028 273 501 197 610 959 276 042 144 972 8;
  • 50) 0.331 382 685 036 264 583 634 667 837 799 062 880 126 370 471 771 028 273 501 197 610 959 276 042 144 972 8 × 2 = 0 + 0.662 765 370 072 529 167 269 335 675 598 125 760 252 740 943 542 056 547 002 395 221 918 552 084 289 945 6;
  • 51) 0.662 765 370 072 529 167 269 335 675 598 125 760 252 740 943 542 056 547 002 395 221 918 552 084 289 945 6 × 2 = 1 + 0.325 530 740 145 058 334 538 671 351 196 251 520 505 481 887 084 113 094 004 790 443 837 104 168 579 891 2;
  • 52) 0.325 530 740 145 058 334 538 671 351 196 251 520 505 481 887 084 113 094 004 790 443 837 104 168 579 891 2 × 2 = 0 + 0.651 061 480 290 116 669 077 342 702 392 503 041 010 963 774 168 226 188 009 580 887 674 208 337 159 782 4;
  • 53) 0.651 061 480 290 116 669 077 342 702 392 503 041 010 963 774 168 226 188 009 580 887 674 208 337 159 782 4 × 2 = 1 + 0.302 122 960 580 233 338 154 685 404 785 006 082 021 927 548 336 452 376 019 161 775 348 416 674 319 564 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:


0.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 959 574 966 967 627 724 076 630 353 541 9(10) =

0.1011 0111 1110 0001 0101 0001 0110 0010 1000 1010 1110 1101 0010 1(2)

5. Positive number before normalization:

2.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 959 574 966 967 627 724 076 630 353 541 9(10) =

10.1011 0111 1110 0001 0101 0001 0110 0010 1000 1010 1110 1101 0010 1(2)

6. Normalize the binary representation of the number.

Shift the decimal mark 1 positions to the left, so that only one non zero digit remains to the left of it:


2.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 959 574 966 967 627 724 076 630 353 541 9(10) =

10.1011 0111 1110 0001 0101 0001 0110 0010 1000 1010 1110 1101 0010 1(2) =

10.1011 0111 1110 0001 0101 0001 0110 0010 1000 1010 1110 1101 0010 1(2) × 20 =

1.0101 1011 1111 0000 1010 1000 1011 0001 0100 0101 0111 0110 1001 01(2) × 21


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): 1

Mantissa (not normalized):
1.0101 1011 1111 0000 1010 1000 1011 0001 0100 0101 0111 0110 1001 01


8. Adjust the exponent.

Use the 11 bit excess/bias notation:


Exponent (adjusted) =

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

1 + 2(11-1) - 1 =

(1 + 1 023)(10) =

1 024(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;
  • 1 024 ÷ 2 = 512 + 0;
  • 512 ÷ 2 = 256 + 0;
  • 256 ÷ 2 = 128 + 0;
  • 128 ÷ 2 = 64 + 0;
  • 64 ÷ 2 = 32 + 0;
  • 32 ÷ 2 = 16 + 0;
  • 16 ÷ 2 = 8 + 0;
  • 8 ÷ 2 = 4 + 0;
  • 4 ÷ 2 = 2 + 0;
  • 2 ÷ 2 = 1 + 0;
  • 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) =

1024(10) =

100 0000 0000(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, by removing the excess bits, from the right (if any of the excess bits is set on 1, we are losing precision...).


Mantissa (normalized) =

1. 0101 1011 1111 0000 1010 1000 1011 0001 0100 0101 0111 0110 1001 01 =

0101 1011 1111 0000 1010 1000 1011 0001 0100 0101 0111 0110 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) =
100 0000 0000

Mantissa (52 bits) =
0101 1011 1111 0000 1010 1000 1011 0001 0100 0101 0111 0110 1001


Decimal number 2.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 959 574 966 967 627 724 076 630 353 541 9 converted to 64 bit double precision IEEE 754 binary floating point representation:

0 - 100 0000 0000 - 0101 1011 1111 0000 1010 1000 1011 0001 0100 0101 0111 0110 1001

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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