Refers to processors where integers and other data are stored in 16-bit registers. The 16-bit designs had only been on the market briefly when 32-bit implementations started to appear.
A 16-bit register can store 2^16 different values. The signed range of integer values that can be stored in 16 bits is −32,768 (−1 × 2^15) through 32,767 (2^15 − 1); the unsigned range is 0 through 65,535 (2^16 − 1). Since 2^16 is 65,536, a processor with 16-bit memory addresses can directly access 64kb of byte-addressable memory.
