## How is overflow detected in two’s complement?

I see that when I subtract positive and negative number using two’s complement I get overflows. For example, if I subtract 1 from 2 I get: So here the result has fifth left bit 10001 – is it overflow? I’ve found these rules for detected overflows with two’s complement: If the sum of two positive numbers yields a negative …

## Why prefer two’s complement over sign-and-magnitude for signed numbers?

It’s done so that addition doesn’t need to have any special logic for dealing with negative numbers. Check out the article on Wikipedia. Say you have two numbers, 2 and -1. In your “intuitive” way of representing numbers, they would be 0010 and 1001, respectively (I’m sticking to 4 bits for size). In the two’s …

## What is “2’s Complement”?

Two’s complement is a clever way of storing integers so that common math problems are very simple to implement. To understand, you have to think of the numbers in binary. It basically says, for zero, use all 0’s. for positive integers, start counting up, with a maximum of 2(number of bits – 1)-1. for negative …