What are the required steps to convert base 10 integer
number -281 470 681 808 928 to signed binary code (in base 2)?
- A signed integer, written in base ten, or a decimal system number, is a number written using the digits 0 through 9 and the sign, which can be positive (+) or negative (-). If positive, the sign is usually not written. A number written in base two, or binary, is a number written using only the digits 0 and 1.
1. Start with the positive version of the number:
|-281 470 681 808 928| = 281 470 681 808 928
2. Divide the number repeatedly by 2:
Keep track of each remainder.
Stop when you get a quotient that is equal to zero.
- division = quotient + remainder;
- 281 470 681 808 928 ÷ 2 = 140 735 340 904 464 + 0;
- 140 735 340 904 464 ÷ 2 = 70 367 670 452 232 + 0;
- 70 367 670 452 232 ÷ 2 = 35 183 835 226 116 + 0;
- 35 183 835 226 116 ÷ 2 = 17 591 917 613 058 + 0;
- 17 591 917 613 058 ÷ 2 = 8 795 958 806 529 + 0;
- 8 795 958 806 529 ÷ 2 = 4 397 979 403 264 + 1;
- 4 397 979 403 264 ÷ 2 = 2 198 989 701 632 + 0;
- 2 198 989 701 632 ÷ 2 = 1 099 494 850 816 + 0;
- 1 099 494 850 816 ÷ 2 = 549 747 425 408 + 0;
- 549 747 425 408 ÷ 2 = 274 873 712 704 + 0;
- 274 873 712 704 ÷ 2 = 137 436 856 352 + 0;
- 137 436 856 352 ÷ 2 = 68 718 428 176 + 0;
- 68 718 428 176 ÷ 2 = 34 359 214 088 + 0;
- 34 359 214 088 ÷ 2 = 17 179 607 044 + 0;
- 17 179 607 044 ÷ 2 = 8 589 803 522 + 0;
- 8 589 803 522 ÷ 2 = 4 294 901 761 + 0;
- 4 294 901 761 ÷ 2 = 2 147 450 880 + 1;
- 2 147 450 880 ÷ 2 = 1 073 725 440 + 0;
- 1 073 725 440 ÷ 2 = 536 862 720 + 0;
- 536 862 720 ÷ 2 = 268 431 360 + 0;
- 268 431 360 ÷ 2 = 134 215 680 + 0;
- 134 215 680 ÷ 2 = 67 107 840 + 0;
- 67 107 840 ÷ 2 = 33 553 920 + 0;
- 33 553 920 ÷ 2 = 16 776 960 + 0;
- 16 776 960 ÷ 2 = 8 388 480 + 0;
- 8 388 480 ÷ 2 = 4 194 240 + 0;
- 4 194 240 ÷ 2 = 2 097 120 + 0;
- 2 097 120 ÷ 2 = 1 048 560 + 0;
- 1 048 560 ÷ 2 = 524 280 + 0;
- 524 280 ÷ 2 = 262 140 + 0;
- 262 140 ÷ 2 = 131 070 + 0;
- 131 070 ÷ 2 = 65 535 + 0;
- 65 535 ÷ 2 = 32 767 + 1;
- 32 767 ÷ 2 = 16 383 + 1;
- 16 383 ÷ 2 = 8 191 + 1;
- 8 191 ÷ 2 = 4 095 + 1;
- 4 095 ÷ 2 = 2 047 + 1;
- 2 047 ÷ 2 = 1 023 + 1;
- 1 023 ÷ 2 = 511 + 1;
- 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;
3. Construct the base 2 representation of the positive number:
Take all the remainders starting from the bottom of the list constructed above.
281 470 681 808 928(10) = 1111 1111 1111 1111 0000 0000 0000 0001 0000 0000 0010 0000(2)
4. Determine the signed binary number bit length:
The base 2 number's actual length, in bits: 48.
- A signed binary's bit length must be equal to a power of 2, as of:
- 21 = 2; 22 = 4; 23 = 8; 24 = 16; 25 = 32; 26 = 64; ...
- The first bit (the leftmost) is reserved for the sign:
- 0 = positive integer number, 1 = negative integer number
The least number that is:
1) a power of 2
2) and is larger than the actual length, 48,
3) so that the first bit (leftmost) could be zero
(we deal with a positive number at this moment)
=== is: 64.
5. Get the positive binary computer representation on 64 bits (8 Bytes):
If needed, add extra 0s in front (to the left) of the base 2 number, up to the required length, 64:
281 470 681 808 928(10) = 0000 0000 0000 0000 1111 1111 1111 1111 0000 0000 0000 0001 0000 0000 0010 0000
6. Get the negative integer number representation:
To get the negative integer number representation on 64 bits (8 Bytes),
... change the first bit (the leftmost), from 0 to 1...
-281 470 681 808 928(10) Base 10 integer number converted and written as a signed binary code (in base 2):
-281 470 681 808 928(10) = 1000 0000 0000 0000 1111 1111 1111 1111 0000 0000 0000 0001 0000 0000 0010 0000
Spaces were used to group digits: for binary, by 4, for decimal, by 3.