Signed Arithmetic
Most operations involving integers are signed
When a number is loaded into a larger field, it is sign extended, which preserves its sign
1111 1111 1111 1101 -3 as hw
1111 1111 1111 1111 1111 1111 1111 1101 -3 as word
0000 0000 0000 0011 3 as hw
0000 0000 0000 0000 0000 0000 0000 0011 3 as word