Logic designer Jim McKevitt and John Bayliss were the lead engineers of the hardware-level development team and Bill Pohlman the manager for the project. Morse with some help from Bruce Ravenel (the architect of the 8087) in refining the final revisions. The architecture was defined by Stephen P. The original chip measured 33 mm² and minimum feature size was 3.2 μm. This was followed by HMOS-II, HMOS-III versions, and, eventually, a fully static CMOS version for battery powered devices, manufactured using Intel's CHMOS processes. It was soon moved to a new refined nMOS manufacturing process called HMOS (for High performance MOS) that Intel originally developed for manufacturing of fast static RAM products. The 8086 was sequenced using a mixture of random logic and microcode and was implemented using depletion-load nMOS circuitry with approximately 20,000 active transistors (29,000 counting all ROM and PLA sites). The 8086 took a little more than two years from idea to working product, which was considered rather fast for a complex design in 1976–1978. The first revision of the instruction set and high level architecture was ready after about three months, and as almost no CAD tools were used, four engineers and 12 layout people were simultaneously working on the chip. Other enhancements included microcoded multiply and divide instructions and a bus structure better adapted to future coprocessors (such as 80) and multiprocessor systems. Morse, this was a result of a more software-centric approach than in the design of earlier Intel processors (the designers had experience working with compiler implementations). According to principal architect Stephen P. Instructions directly supporting nested ALGOL-family languages such as Pascal and PL/M were also added.
EMU8086 REGISTER KEY FULL
New kinds of instructions were added as well full support for signed integers, base+offset addressing, and self-repeating operations were akin to the Z80 design but were all made slightly more general in the 8086. However, the 8086 design was expanded to support full 16-bit processing. The programming model and instruction set is (loosely) based on the 8080 in order to make this possible. Marketed as source compatible, the 8086 was designed to allow assembly language for the 8008, 8080, or 8085 to be automatically converted into equivalent (suboptimal) 8086 source code, with little or no hand-editing. Both the architecture and the physical chip were therefore developed rather quickly by a small group of people, and using the same basic microarchitecture elements and physical implementation techniques as employed for the slightly older 8085 (and for which the 8086 also would function as a continuation). It was an attempt to draw attention from the less-delayed 16- and 32-bit processors of other manufacturers (such as Motorola, Zilog, and National Semiconductor) and at the same time to counter the threat from the Zilog Z80 (designed by former Intel employees), which became very successful. The 8086 project started in May 1976 and was originally intended as a temporary substitute for the ambitious and delayed iAPX 432 project. Other well known 8-bit microprocessors that emerged during these years are Motorola 6800 (1974), General Instrument PIC16X (1975), MOS Technology 6502 (1975), Zilog Z80 (1976), and Motorola 6809 (1978). The 8080 device was eventually replaced by the depletion-load-based 8085 (1977), which sufficed with a single +5 V power supply instead of the three different operating voltages of earlier chips. It has an extended instruction set that is source-compatible (not binary compatible) with the 8008 and also includes some 16-bit instructions to make programming easier. Two years later, Intel launched the 8080, employing the new 40-pin DIL packages originally developed for calculator ICs to enable a separate address bus. The device needed several additional ICs to produce a functional computer, in part due to it being packaged in a small 18-pin "memory package", which ruled out the use of a separate address bus (Intel was primarily a DRAM manufacturer at the time). It implemented an instruction set designed by Datapoint corporation with programmable CRT terminals in mind, which also proved to be fairly general-purpose. In 1972, Intel launched the 8008, the first 8-bit microprocessor.
0 kommentar(er)
