The Zilog Z80000 is an unreleased

32-bit In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in a maximum of 32- bit units. Compared to smaller bit widths, 32-bit computers can perform la ...

processor designed by

Zilog Zilog, Inc. is an American manufacturer of microprocessors, microcontrollers, and application-specific embedded System on a chip, system-on-chip (SoC) products. The company was founded in 1974 by Federico Faggin and Ralph Ungermann, who were soo ...

and completed in 1986. The Z80000 is a 32-bit expansion of the

16-bit 16-bit microcomputers are microcomputers that use 16-bit microprocessors. A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two ...

Zilog Z8000 The Zilog Z8000 is a 16-bit microprocessor architecture designed by Zilog and introduced in early 1979. Two chips were initially released, differing only in the width of the address bus; the Z8001 had a 23-bit bus while the Z8002 had a 16-bit b ...

with

multiprocessing Multiprocessing (MP) is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. The ...

capability, a six-stage

instruction pipeline In computer engineering, instruction pipelining is a technique for implementing instruction-level parallelism within a single processor. Pipelining attempts to keep every part of the processor busy with some instruction by dividing incoming Mac ...

, and a 256-byte cache. It can address 4

gigabyte The gigabyte () is a multiple of the unit byte for digital information. The SI prefix, prefix ''giga-, giga'' means 109 in the International System of Units (SI). Therefore, one gigabyte is one billion bytes. The unit symbol for the gigabyte i ...

s of

RAM Ram, ram, or RAM most commonly refers to: * A male sheep * Random-access memory, computer memory * Ram Trucks, US, since 2009 ** List of vehicles named Dodge Ram, trucks and vans ** Ram Pickup, produced by Ram Trucks Ram, ram, or RAM may also ref ...

, but cannot execute code written for the Z8000 or

Z80 The Zilog Z80 is an 8-bit microprocessor designed by Zilog that played an important role in the evolution of early personal computing. Launched in 1976, it was designed to be software-compatible with the Intel 8080, offering a compelling altern ...

. Described at the time as a "

mainframe A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterpris ...

on a chip", the processor is in many ways an equivalent to

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

80386 The Intel 386, originally released as the 80386 and later renamed i386, is the third-generation x86 architecture microprocessor from Intel. It was the first 32-bit processor in the line, making it a significant evolution in the x86 architect ...

. Delays in the initial manufacturing pushed back its availability date to after that of the 386, and the Z80000 only made it to a test sampling phase without ever being released commercially.

Description

Like the Z8000 it is based on, the Z80000 has sixteen general-purpose registers, but expanded from the Z8000's 16-bit to 32-bit. Like the Z8000, the Z80000 allows its registers to be combined, in this case using two 32-bit registers to act as a single 64-bit one. To support the Z8000s 16-bit wide data, the Z80000 can place two 16-bit values in a single 32-register. The processor includes a

memory management unit A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware unit that examines all references to computer memory, memory, and translates the memory addresses being referenced, known as virtual mem ...

that provides

protected memory Memory protection is a way to control memory access rights on a computer, and is a part of most modern instruction set architectures and operating systems. The main purpose of memory protection is to prevent a process from accessing memory that h ...

, important for multitasking, and

virtual memory In computing, virtual memory, or virtual storage, is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a ver ...

addressing for temporary storage of RAM on a

hard disk A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating hard disk drive platter, pla ...

. The processor has three methods of accessing memory: * compact mode – meant for small programs, could only access 64 KB (16-bit addresses, equivalent to the Z8000's non-segmented mode). Address bits 31-16 of all virtual addresses comes from address bits 31-16 of the program counter. * segmented mode – 32,768 segments of 64 KB (16-bit address; comprising memory from 0-2GB) ''and'' 128 segments of 16 MB (24-bit address; comprising memory from 2GB-4GB), making a total of 4 GB (32-bit address) of accessible memory. * linear mode – direct 4 GB (32-bit address) accessible memory On the Z80000 CPU, interrupts are part of a category known as exceptions. This category includes resets, bus errors, interrupts, and traps. The processor is designed to interoperate with other

integrated circuit An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...

s designed for use with the Z8000, such as the

Zilog Z8070 Zilog, Inc. is an American manufacturer of microprocessors, microcontrollers, and application-specific embedded system-on-chip (SoC) products. The company was founded in 1974 by Federico Faggin and Ralph Ungermann, who were soon joined by M ...

floating-point In computing, floating-point arithmetic (FP) is arithmetic on subsets of real numbers formed by a ''significand'' (a Sign (mathematics), signed sequence of a fixed number of digits in some Radix, base) multiplied by an integer power of that ba ...

coprocessor A coprocessor is a computer processor used to supplement the functions of the primary processor (the CPU). Operations performed by the coprocessor may be floating-point arithmetic, graphics, signal processing, string processing, cryptography or ...

. The Z320 was the

CMOS Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss ", , ) is a type of MOSFET, metal–oxide–semiconductor field-effect transistor (MOSFET) semiconductor device fabrication, fabrication process that uses complementary an ...

version of the Z80000.

References

External links

Z80000 at ''Great Microprocessors of the Past and Present''

Zilog Z80,000™ CPU Product Specification
October 1988 at Datasheet Archive
Zilog Z8000 Family Architecture - A High-Performance 16-Bit Architecture With 32-Bit Migration - Z8000™ 16 Bit CPU's - Z80,000™ 32 Bit CPU's
at Datasheet Archive Zilog microprocessors 32-bit microprocessors {{microcompu-stub