Simplest way to check if two integers have same sign?

Question

Which is the simplest way to check if two integers have same sign? Is there any short bitwise trick to do this?

Answer 1

As a technical note, bit-twiddly solutions are going to be much more efficient than multiplication, even on modern architectures. It's only about 3 cycles that you're saving, but you know what they say about a "penny saved"...