[prev] 51 [next]

Signed integers (cont)

Several possible representations for negative values
  • signed magnitude ... first bit is sign, rest are magnitude
  • ones complement ... form -N by inverting all bits in N
  • twos complement ... form -N by inverting N and adding 1
In all representations, +ve numbers have 0 in leftmost bit

Examples: representations of (8-bit) -5 (where 5 is 00000101)

  • 10000101 ... signed magnitude
  • 11111010 ... ones complement
  • 11111011 ... twos complement