320xx microprocessor
320xx isseriesmicroprocessors from National Semiconductor. The 320xx processors havecoprocessor interface which allows coprocessors such as FPUsMMUsbe attached inchain.The 320xx waspredecessor ofSwordfish microprocessor.
The first chip inseries was originally called 16032, later renamed 32016. It became available inlate 1970s,may have beenfirst 32 bit chipreach mass productionsale (at least accordingNational Semiconductor marketing hype.)
This chip had16 bit external databus, 24 bit external address bus, andfull 32 bit instruction set. The instruction set was extremely complex but mostly regular, withlarge setaddressing modes. It was somewhat similarspirit(but not compatible with)popular DEC VAX minicomputer instructions set.
National Semiconductor also produced related chipsfloating point, memory management,DMA. Withfull set plus memoryperipherals,was feasiblebuild32 bit computer system capablesupporting modern multi-tasking operating systems, something that had previously been possible only on expensive minicomputersmainframes.
The 32032 arrived soon afterwards. It was almost completely compatible, but featured32 bit data bus (and i think31 bit address bus?)somewhat faster performance. Boththese early chips were notoriousbeing unrealiable. There wassomewhat better chancegetting themwork iffull setCPU, MMU, FPU, DMA chip were purchased asmatched, tested set, from Natsemi. Nonetheless, reliability trouble madeearly 320XX fairly unpopular,Natsemi were forcedsell them at much lower prices thancompeting Motorola 68000ordersell any at all. This low price did at least make them somewhat popularhobbiests wantingbuild 32 bit computers onvery small budget.
During1980s, successor chips called3233232532 arrived, maintaininggood degreecompatibility,much improved reliabilityperformance. By thendamagereputation had been done,these chips were (probably unjustly) ignored by most ofmarket.
The Swordfish wasfurther advance, aimed at embedded systemsarriving circa 1990. They had some success inlaser printer market, despite intense competition from AMDIntel RISC chips.
There wascompletely different 320xx series made by Western Digital, another by Texas Instrumentsprobably others made by other companies. I thinklotcompanies thoughtwasobvious name forseries32 bit microprocessors.
Some material from FOLDOC, usedpermission.
