NS320xx

The NS320xx were a family of 32 -bit processors from National Semiconductor, which were characterized by an extensive command set.

Development

The first presented processor family was the NS16032 (later renamed NS32016 ). , This possessed externally via a 16 bit wide data bus and appeared about 1979 on the market In 1984, the NS32032 with a complete 32-bit wide data bus, and significantly increased performance. Also available was the NS32008 which should find a reduced to 8-bit data bus as an embedded processor a place in the market, but had little success.

With the following NS32332 and NS32532, the performance was further increased. The planned NS32732 then, however, never reached the market. Parts of the development for the NS32732 were then used for specialized processors that are suited to the control of laser printers. Meanwhile, the NS32000 family has been completely set.

  • CPU 8 -bit data and 24- bit address
  • 16 -bit data and 24- bit address
  • CPU with 32- bit data and 24- bit address
  • For multiprocessor systems
  • Data sheets are available, but the existence of this CPU is not busy.
  • CPU with 32-bit data and address bus
  • Compatible with NS32081 FPU or NS32381
  • CPU with 32-bit data and address bus
  • 512 byte instruction cache
  • 1024 bytes data cache
  • 320,000 transistors
  • FPU
  • Compatible with the CPUs NS32008, NS32016, NS32032, NS32132 and NS32332
  • Support 32- bit and 64 -bit operations
  • This FPU is software compatible to NS32081
  • Compatible with all CPUs of the NS32000 family

Architecture and instruction set

What is remarkable about the NS32xxx was completely shut off from the beginning on 32 bit style. Between the different generations of processors, there were only minimal differences in the instruction set. The first implemented as coprocessors MMU and FPU functions were integrated in subsequent generations of chips in the processor without requiring major adjustments of the software were necessary.

The instruction set was very extensive, as are the addressing modes. Various combinations of index and offset registers allowed direct access to complex data structures with a single command. All commands were for each of its data source or destination addresses or any addressing mode register and use many commands could work with two source and a destination address. From the standpoint of symmetry and orthogonality of the instruction set of the NS320xx family is likely the culmination of which constitute what has been realized - a Complex Instruction Set Computer ( CISC ) ​​, in the truest sense of the word.

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