How to present negative number in bitvector?

Question

The title says it all. I try to present -1 as the following: (_ bv-1 32), and z3 complains.

How do I present constraint such as 3x - 5y <= 10 in bit vector? For some reason, I do not want to use linear integer.

score 2 · Accepted Answer · answered May 05 '16 at 11:19

2

This is usually done via two's complement encoding. The short version is,

-x = flip(x) + 1

where flip(x) simply flips all the bits in x.

answered May 05 '16 at 11:19

Thank you. What is the syntax to flip all the bits in SMTLIB2 format? – sean May 05 '16 at 17:57
1

That should be (bvnot x). – Christoph Wintersteiger May 13 '16 at 13:55

1 Answers1