Zilog Z8000

The processor Zilog Z8000 was introduced in 1979 shortly after the Intel 8086. This CPU was rebuilt in the GDR under the name U8001/U8002 and offered from 1984.

It is a 16-bit processor, which consists of 16 16- bit registers. He also owns advanced 32 -bit multiply- and Dividierbefehle and a DRAM refreshing circuit but it is considered slow. He has different processing modes for the operating system and application programs to prevent access to specific memory areas.

The memory addressability falls depending on the model of: The Z8001 is 8 MB ​​and the Z8002 address by segmented addressing only 64KB. An external MMU (Memory Management Unit) in the model Z8010, the address space can be expanded to 48 MB.

The maximum clock rate is 4 to 10 MHz.

Because of initial errors, the processor could not prevail and was built in contrast to his predecessor Z80 only a few computers such as the Commodore 900 or Olivetti M20. He was also used pole position in the control and target system of the Tomahawk cruise missile and the arcade game. In the GDR it was used in the P8000.

Mid-1980s, five 16- bit processors are available on the market mainly ( work internally this partly also with 32 bit key for the circuit complexity bus interface was but 16 bits in size ): Intel i8086, Motorola 68000, Zilog with Z8000, National Semiconductor NS16032 and TI with the TMS 9900th the non-Intel suppliers could the market dominance of Intel, despite good processor architecture not stop them, because the PC market was predetermined by IBM. Zilog had chosen for reasons of time, hardwired to implement the instruction set of the Z8000 and not - like Motorola - through micro- programming. The correction of hardware bugs took considerably more time than the competitors', so that many customers bailed and switched to competitors. TI was generally too late, so no more market success was given.

The successor is the Z80000.