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16-bit
microcomputer A microcomputer is a small, relatively inexpensive computer with a microprocessor as its central processing unit (CPU). It includes a microprocessor, Computer memory, memory and minimal input/output (I/O) circuitry mounted on a single printed ci ...
s are computers in which 16-bit
microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip ...

microprocessor
s were the norm. A 16-bit register can store 216 different values. The
range Range may refer to: Geography * Range (geographic)A range, in geography, is a chain of hill A hill is a landform A landform is a natural or artificial feature of the solid surface of the Earth or other planetary body. Landforms together ...
of
integer An integer (from the Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to ...
values that can be stored in 16 bits depends on the integer representation used. With the two most common representations, the range is 0 through 32,767 (215 − 1) for representation as an (
unsigned Unsigned can refer to: * An unsigned artist is a musical artist or group not attached or signed to a record label ** Unsigned Music Awards, ceremony noting achievements of unsigned artists ** Unsigned band web, online community * Similarly, the con ...
)
binary number In mathematics and digital electronics Digital electronics is a field of electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons The electr ...
, and −32,768 (−1 × 215) through 32,767 (215 − 1) for representation as
two's complement Two's complement is a mathematical operation In mathematics, an operation is a Function (mathematics), function which takes zero or more input values (called ''operands'') to a well-defined output value. The number of operands is the arity of the ...
. Since 216 is 65,536, a processor with 16-bit
memory address In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softwa ...
es can directly access 64 KB (65,536 bytes) of byte-addressable memory. If a system uses
segmentation Segment or segmentation may refer to: Biology *Segmentation (biology), the division of body plans into a series of repetitive segments **Segmentation in the human nervous system *Internodal segment, the portion of a nerve fiber between two Nodes of ...
with 16-bit segment offsets, more can be accessed.


16-bit architecture

The MIT Whirlwind ( 1951) was quite possibly the first-ever 16-bit computer. Other early 16-bit computers ( 1965–70) include the
IBM 1130 The IBM 1130 Computing System, introduced in 1965, was IBM International Business Machines Corporation (IBM) is an American multinational technology company headquartered in Armonk, New York, with operations in over 170 countries. The co ...
, the
HP 2100 The HP 2100 is a series of 16-bit 16-bit microcomputers are computers in which 16-bit microprocessors were the norm. A 16-bit register can store 216 different values. The range (computer programming), range of integer values that can be stored in ...
, the
Data General Nova The Data General Nova is a series of 16-bit 16-bit microcomputers are computers in which 16-bit microprocessors were the norm. A 16-bit register can store 216 different values. The range (computer programming), range of integer values that ca ...
, and the DEC PDP-11. Early multi-chip
16-bit microprocessors 16-bit microcomputers are computers in which 16-bit microprocessors were the norm. A 16-bit register can store 216 different values. The range (computer programming), range of integer values that can be stored in 16 bits depends on the Integer (c ...
( 1973–76) include the five-chip National Semiconductor IMP-16 (1973), the two-chip
NEC is a Japanese multinational information technology and electronics Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. It uses active d ...
μCOM-16 (1974), the three-chip Western Digital MCP-1600 (1975), and the five-chip
Toshiba is a Japanese multinational Multinational may refer to: * Multinational corporation, a corporate organization operating in multiple countries * Multinational force, a military body from multiple countries * Multinational state, a sovereign st ...
T-3412 (1976). Early single-chip 16-bit microprocessors ( 1975–76) include the
Panafacom is a Japanese information technology company. The company was formed by the merger of Panafacom and USAC Electronic Industrial in 1987. As of 2019, PFU focuses on computing and IT consulting. Its product line includes image scanner An image sc ...
MN1610 (1975),
National Semiconductor PACE National Semiconductor's IPC-16A PACE, short for "Processing and Control Element", was the first commercial single-chip 16-bit microprocessor, announced in late 1974. It was a single-chip implementation of their early 1973 five-chip IMP-16 architec ...
(1975),
General Instrument CP1600 The CP1600 is a 16-bit 16-bit microcomputers are computers in which 16-bit microprocessors were the norm. A 16-bit register can store 216 different values. The range (computer programming), range of integer values that can be stored in 16 bits de ...
(1975),
Texas Instruments TMS9900 Introduced in June 1976, the TMS9900 was one of the first commercially available, single-chip 16-bit 16-bit microcomputers are computers in which 16-bit microprocessors were the norm. A 16-bit register can store 216 different values. The range ...
(1976),
Ferranti F100-L The Ferranti F100-L was a 16-bit 16-bit microcomputer A microcomputer is a small, relatively inexpensive computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. M ...
, and the HP BPC. Other notable 16-bit processors include the
Intel 8086 The 8086 (also called iAPX 86) is a 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. The Intel 8088, released July 1, 1979, is a slightly modified chip with an external 8-bit Bus (computing), ...
, the
Intel 80286 The Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is the ...

Intel 80286
, the
WDC 65C816 The W65C816S (also 65C816 or 65816) is an 8/16-bit microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The ...
, and the
Zilog Z8000 The Z8000 ("''zee-'' or ''zed-eight-thousand''") is a 16-bit 16-bit microcomputers are computers in which 16-bit microprocessors were the norm. A 16-bit register can store 216 different values. The range (computer programming), range of intege ...
. The
Intel 8088 The Intel 8088 ("''eighty-eighty-eight''", also called iAPX 88) microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit An integrated circuit or ...
was
binary compatible Binary-code compatibility (binary compatible or object-code-compatible) is a property of computer systems meaning that they can run the same executable code In computing, executable code, an executable file, or an executable program, sometimes ...
with the Intel 8086, and was 16-bit in that its registers were 16 bits wide, and arithmetic instructions could operate on 16-bit quantities, even though its external bus was 8 bits wide. A 16-bit integer can store 216 (or 65,536) distinct values. In an
unsigned Unsigned can refer to: * An unsigned artist is a musical artist or group not attached or signed to a record label ** Unsigned Music Awards, ceremony noting achievements of unsigned artists ** Unsigned band web, online community * Similarly, the con ...
representation, these values are the integers between and 65,535; using
two's complement Two's complement is a mathematical operation In mathematics, an operation is a Function (mathematics), function which takes zero or more input values (called ''operands'') to a well-defined output value. The number of operands is the arity of the ...
, possible values range from −32,768 to 32,767. Hence, a processor with 16-bit
memory address In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softwa ...
es can directly access 64 KB of byte-addressable memory. 16-bit processors have been almost entirely supplanted in the
personal computer A personal computer (PC) is a multi-purpose computer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or technician ...
industry, and are used less than 32-bit (or 8-bit) CPUs in embedded applications.


16/32-bit Motorola 68000 and Intel 386SX

The
Motorola 68000 The Motorola 68000 (sometimes shortened to Motorola 68k or m68k and usually pronounced "sixty-eight-thousand") is a 16/32-bit complex instruction set computer A complex instruction set computer (CISC ) is a computer in which single instructi ...
is sometimes called ''16-bit'' because its internal and external data buses were 16 bits wide; however, it could be considered a
32-bit 32-bit microcomputer A microcomputer is a small, relatively inexpensive computer with a microprocessor as its central processing unit (CPU). It includes a microprocessor, Computer memory, memory and minimal input/output (I/O) circuitry mount ...
processor in that the general purpose registers were 32 bits wide and most arithmetic instructions supported 32-bit arithmetic. The 68000 was a
microcode In processor design Processor design is a subfield of computer engineering and electronics engineering (fabrication) that deals with creating a processor (computing), processor, a key component of computer hardware. The design process involves c ...
d processor with three internal 16-bit ALUs. Only 24 bits of the
program counter The program counter (PC), commonly called the instruction pointer (IP) in Intel Intel Corporation is an American multinational corporation A multinational company (MNC) is a corporate A corporation is an organization—usually a gr ...
(PC) were available on original DIP packages, with up to 16 megabytes of addressable
RAM Random-access memory (RAM; ) is a form of computer memory In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic proces ...
. 68000 software is 32-bit in nature and forward-compatible with other 32-bit processors in the same family. The 68008 was a version of the 68000 with an 8-bit external data path and 1-megabyte addressing for the 48-pin DIP version, and 4 megabytes for the 52-pin PLCC version. Several
Apple An apple is an edible fruit In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this fie ...
Macintosh The Macintosh (mainly Mac since 1998) is a family of personal computer A personal computer (PC) is a multi-purpose computer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be op ...

Macintosh
models--e.g., the LC series--used 32-bit 68020 and 68030 processors on a 16-bit data bus to save cost. Similar analysis applies to Intel's
80286 The Intel Intel Corporation is an American multinational corporation A multinational company (MNC) is a corporate A corporation is an organization—usually a group of people or a company A company, abbreviated as co., is a Le ...
CPU replacement, called the
386SX#REDIRECT I386 The Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, Santa Clara, California, in Silicon Valley. It is the world's largest semiconductor chip ...
, which is a 32-bit processor with 32-bit ALU and internal 32-bit data paths with a 16-bit external bus and 24-bit addressing of the processor it replaced.


16-bit application

In the context of
IBM PC compatible IBM PC compatible computers are similar to the original IBM PC The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first computer released in the IBM PC model line and the basis for the IBM PC compatible IBM PC c ...
and
Wintel Wintel is the partnership of Microsoft Windows Microsoft Windows, commonly referred to as Windows, is a group of several proprietary {{Short pages monitor