| Integers: excess/bias | |||||||||||
| One disadvantage of 2C: | |||||||||||
| Can't sort values just using the bit representation. | |||||||||||
| Would look like negative numbers were greater than positive numbers. | |||||||||||
| Another idea: | |||||||||||
| Consider the unsigned values for a 3-bit representation | |||||||||||
| representation | value | excess-4 | |||||||||
| 000 | 0 | -4 | |||||||||
| 001 | 1 | -3 | |||||||||
| 010 | 2 | -2 | |||||||||
| 011 | 3 | -1 | |||||||||
| 100 | 4 | 0 | |||||||||
| 101 | 5 | 1 | |||||||||
| 110 | 6 | 2 | |||||||||
| 111 | 7 | 3 | |||||||||
| Represent negative values, but keep the values in representation order | |||||||||||
| First half of the representations for negative, second half for positive | |||||||||||
| This is called excess, or biased, representation. | |||||||||||
| Each value is shifted by a constant amount; in this case the bias is 4. | |||||||||||
| Since there are 3 bits, the bias value is 2(3-1) = 4 | |||||||||||