Computing in Security (Conversion Help)
posted by Francesca on .
1.) Express each decimal number as an 8-bit binary number in the 2's complement form and then find the negative of the representation of that number in two’s compliment
Thanks for any help!
Two's complement is a notation that represents both positive and negative numbers. The most significant (left-most) is the sign bit, which is turned on when the number is negative.
Unlike the one's complement, there is only one representation of zero.
For an eight-bit number, the range goes from -128 to 127.
A positive number is represented by a usual binary number format, using the 7 low-order (right-most) bits, and represent from 0 to 127.
A negative number is simply the reversal of the bits and then add 1.
-10(decimal)=11110101 + 1
-18(decimal)=11101101 + 1
and so on.
To negate a negative number, subtract one and reverse the bits.
00010010 (binary -18)