Question

What is - on bitvectors?

Answer

The - operator for bit-vectors is subtraction or unary negation. Unary negation, - b is equivalent to 0 - b. This is not the same as complement, which is written as ! b.

For example, the bv5 value equivalent to the natural number 13 is 01101.

• The complement of this value is 10010, which is 18.
• The negation of this value is 10011, which is 19.

In 2’s complement fixed-bit-width arithmetic, -x is !x + 1.