64bit IEEE 754: Decimal ↗ Double Precision Floating Point Binary: 0.566 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 6 Convert the Number to 64 Bit Double Precision IEEE 754 Binary Floating Point Representation Standard, From a Base Ten Decimal System Number

Number 0.566 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 6(10) converted and written in 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: 0.566 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 6.

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) 0.566 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 6 × 2 = 1 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 2;
  • 2) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 4;
  • 3) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 332 8;
  • 4) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 332 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 665 6;
  • 5) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 665 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 331 2;
  • 6) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 331 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 662 4;
  • 7) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 662 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 324 8;
  • 8) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 324 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 649 6;
  • 9) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 649 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 299 2;
  • 10) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 299 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 598 4;
  • 11) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 598 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 196 8;
  • 12) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 196 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 393 6;
  • 13) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 393 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 332 787 2;
  • 14) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 332 787 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 665 574 4;
  • 15) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 665 574 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 331 148 8;
  • 16) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 331 148 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 662 297 6;
  • 17) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 662 297 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 324 595 2;
  • 18) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 324 595 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 649 190 4;
  • 19) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 649 190 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 298 380 8;
  • 20) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 298 380 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 596 761 6;
  • 21) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 596 761 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 193 523 2;
  • 22) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 333 193 523 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 387 046 4;
  • 23) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 387 046 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 332 774 092 8;
  • 24) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 332 774 092 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 665 548 185 6;
  • 25) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 665 548 185 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 331 096 371 2;
  • 26) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 331 096 371 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 662 192 742 4;
  • 27) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 662 192 742 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 324 385 484 8;
  • 28) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 324 385 484 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 648 770 969 6;
  • 29) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 648 770 969 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 297 541 939 2;
  • 30) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 333 297 541 939 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 595 083 878 4;
  • 31) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 666 595 083 878 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 190 167 756 8;
  • 32) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 333 190 167 756 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 380 335 513 6;
  • 33) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 666 380 335 513 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 332 760 671 027 2;
  • 34) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 332 760 671 027 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 665 521 342 054 4;
  • 35) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 665 521 342 054 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 331 042 684 108 8;
  • 36) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 331 042 684 108 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 662 085 368 217 6;
  • 37) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 662 085 368 217 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 324 170 736 435 2;
  • 38) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 324 170 736 435 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 648 341 472 870 4;
  • 39) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 648 341 472 870 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 296 682 945 740 8;
  • 40) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 333 296 682 945 740 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 593 365 891 481 6;
  • 41) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 666 593 365 891 481 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 186 731 782 963 2;
  • 42) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 333 186 731 782 963 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 373 463 565 926 4;
  • 43) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 666 373 463 565 926 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 332 746 927 131 852 8;
  • 44) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 332 746 927 131 852 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 665 493 854 263 705 6;
  • 45) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 665 493 854 263 705 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 330 987 708 527 411 2;
  • 46) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 330 987 708 527 411 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 661 975 417 054 822 4;
  • 47) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 661 975 417 054 822 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 323 950 834 109 644 8;
  • 48) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 323 950 834 109 644 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 647 901 668 219 289 6;
  • 49) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 647 901 668 219 289 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 333 295 803 336 438 579 2;
  • 50) 0.133 333 333 333 333 333 333 333 333 333 333 333 333 295 803 336 438 579 2 × 2 = 0 + 0.266 666 666 666 666 666 666 666 666 666 666 666 666 591 606 672 877 158 4;
  • 51) 0.266 666 666 666 666 666 666 666 666 666 666 666 666 591 606 672 877 158 4 × 2 = 0 + 0.533 333 333 333 333 333 333 333 333 333 333 333 333 183 213 345 754 316 8;
  • 52) 0.533 333 333 333 333 333 333 333 333 333 333 333 333 183 213 345 754 316 8 × 2 = 1 + 0.066 666 666 666 666 666 666 666 666 666 666 666 666 366 426 691 508 633 6;
  • 53) 0.066 666 666 666 666 666 666 666 666 666 666 666 666 366 426 691 508 633 6 × 2 = 0 + 0.133 333 333 333 333 333 333 333 333 333 333 333 332 732 853 383 017 267 2;

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...)


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:


0.566 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 6(10) =


0.1001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0(2)


5. Positive number before normalization:

0.566 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 6(10) =


0.1001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0(2)

6. Normalize the binary representation of the number.

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


0.566 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 6(10) =


0.1001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0(2) =


0.1001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0001 0(2) × 20 =


1.0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010(2) × 2-1


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):
1.0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010


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) =


1 022(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;
  • 1 022 ÷ 2 = 511 + 0;
  • 511 ÷ 2 = 255 + 1;
  • 255 ÷ 2 = 127 + 1;
  • 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) =


1022(10) =


011 1111 1110(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. 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 =


0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010


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 1110


Mantissa (52 bits) =
0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010


The base ten decimal number 0.566 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 666 6 converted and written in 64 bit double precision IEEE 754 binary floating point representation:
0 - 011 1111 1110 - 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010

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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