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16-497: It runs on the HP 3000 family of computers, which originally used HP custom 16-bit stack architecture CISC CPUs and were later migrated to PA-RISC where the operating system was called MPE XL . In 1983, the original version of MPE was written in a language called SPL ( System Programming Language ). MPE XL was written primarily in Pascal , with some assembly language and some of

32-443: A 20- bit or 24-bit segment or selector-offset address representation to extend the range of addressable memory locations beyond what was possible using only 16-bit addresses. Programs containing more than 2 bytes (65,536 bytes ) of instructions and data therefore required special instructions to switch between their 64-kilobyte segments , increasing the complexity of programming 16-bit applications. Panafacom Panafacom

48-717: A similar fashion, later 68000-family members, starting with the Motorola 68020 , had 32-bit ALUs. One may also see references to systems being, or not being, 16-bit based on some other measure. One common one is when the address space is not the same size of bits as the internal registers. Most 8-bit CPUs of the 1970s fall into this category; the MOS 6502 , Intel 8080 , Zilog Z80 and most others had 16-bit address space which provided 64 KB of address space. This also meant address manipulation required two instruction cycles. For this reason, most processors had special 8-bit addressing modes,

64-416: Is sometimes called 16-bit because of the way it handles basic arithmetic. The instruction set was based on 32-bit numbers and the internal registers were 32 bits wide, so by common definitions, the 68000 is a 32-bit design. Internally, 32-bit arithmetic is performed using two 16-bit operations, and this leads to some descriptions of the system as 16-bit, or "16/32". Such solutions have a long history in

80-451: The 386SX , 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. In the context of IBM PC compatible and Wintel platforms, a 16-bit application is any software written for MS-DOS , OS/2 1.x or early versions of Microsoft Windows which originally ran on the 16-bit Intel 8088 and Intel 80286 microprocessors . Such applications used

96-690: The Intel 80286 , the WDC 65C816 , and the Zilog Z8000 . The Intel 8088 was binary compatible 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. 16-bit processors have been almost entirely supplanted in the personal computer industry, and are used less than 32-bit (or 8-bit) CPUs in embedded applications. The Motorola 68000

112-513: The integer representation used. With the two most common representations, the range is 0 through 65,535 (2 − 1) for representation as an ( unsigned ) binary number , and −32,768 (−1 × 2 ) through 32,767 (2 − 1) for representation as two's complement . Since 2 is 65,536, a processor with 16-bit memory addresses can directly access 64 KB (65,536 bytes) of byte-addressable memory. If a system uses segmentation with 16-bit segment offsets, more can be accessed. The MIT Whirlwind ( c. 1951)

128-520: The zero page , improving speed. This sort of difference between internal register size and external address size remained in the 1980s, although often reversed, as memory costs of the era made a machine with 32-bit addressing, 2 or 4 GB, a practical impossibility. For example, the 68000 exposed only 24 bits of addressing on the DIP , limiting it to a still huge (for the era) 16 MB. A similar analysis applies to Intel's 80286 CPU replacement, called

144-627: The 1960s, especially on minicomputer systems. Early 16-bit computers ( c. 1965–70) include the IBM 1130 , the HP 2100 , the Data General Nova , and the DEC PDP-11 . Early 16-bit microprocessors , often modeled on one of the mini platforms, began to appear in the 1970s. Examples ( c. 1973–76) include the five-chip National Semiconductor IMP-16 (1973), the two-chip NEC μCOM-16 (1974),

160-503: The computer field, with various designs performing math even one bit at a time, known as "serial arithmetic", while most designs by the 1970s processed at least a few bits at a time. A common example is the Data General Nova, which was a 16-bit design that performed 16-bit math as a series of four 4-bit operations. 4-bits was the word size of a widely available single-chip ALU and thus allowed for inexpensive implementation. Using

176-525: The definition being applied to the 68000, the Nova would be a 4-bit computer, or 4/16. Not long after the introduction of the Nova, a second version was introduced, the SuperNova, which included four of the 4-bit ALUs running in parallel to perform math 16 bits at a time and therefore offer higher performance. This was invisible to the user and the programs, which always used 16-bit instructions and data. In

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192-694: The following list of common commands and programs. This operating-system -related article is a stub . You can help Misplaced Pages by expanding it . 16-bit In computer architecture , 16-bit integers , memory addresses , or other data units are those that are 16 bits (2 octets ) wide. Also, 16-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers , address buses , or data buses of that size. 16-bit microcomputers are microcomputers that use 16-bit microprocessors . A 16-bit register can store 2 different values. The range of integer values that can be stored in 16 bits depends on

208-474: The old SPL code. In 1992, the OS name was changed to MPE/iX to indicate Unix interoperability with the addition of POSIX compatibility. The discontinuance of the product line was announced in late 2001, with support from HP terminating at the end of 2010. A number of 3rd party companies still support both the hardware and software. In 2002 HP released the last version MPE/iX 7.5. Among others, MPE/iX supports

224-519: The three-chip Western Digital MCP-1600 (1975), and the five-chip Toshiba T-3412 (1976). Early single-chip 16-bit microprocessors ( c. 1975–76) include the Panafacom MN1610 (1975), National Semiconductor PACE (1975), General Instrument CP1600 (1975), Texas Instruments TMS9900 (1976), Ferranti F100-L , and the HP BPC . Other notable 16-bit processors include the Intel 8086 ,

240-548: Was a Japanese microprocessor design firm established on 2 July 1973 by a consortium of companies that included Fujitsu , Fuji Electric and Matsushita (Panasonic). The company was formed to design and manufacture the MN1610 , a 16-bit microprocessor . The MN1610 was released in April 1975, becoming one of the world's first single-chip 16-bit microprocessors. The design saw relatively little use and remains largely unknown in

256-443: Was quite possibly the first-ever 16-bit computer. It was an unusual word size for the era; most systems used six-bit character code and used a word length of some multiple of 6-bits. This changed with the effort to introduce ASCII , which used a 7-bit code and naturally led to the use of an 8-bit multiple which could store a single ASCII character or two binary coded decimal digits. The 16-bit word length thus became more common in

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