[time-nuts] favorite microcontroller module?

Mike S mikes at flatsurface.com
Thu Feb 21 12:25:34 EST 2008


At 10:17 AM 2/21/2008, Chuck Harris wrote...
>Sorry, but that is not so.  The 68000 was a 16 bit machine, both 
>internally, and externally, with 32 bit registers and some 32 bit 
>instructions.

Your Intel bias is really showing now. Enough with trying to change the 
subject. The discussion was in regard to architecture, not 
implementation.

Your original claim was "It would have been impossible for intel to put 
a 32 bit bus and register set on a processor like the 8086 back in 
1978." That was in support of Intel's segmented memory _architecture._

That claim is disproved by the fact that the 68000, which first shipped 
in 1979, had a 32 bit architecture. That the first implementation 
didn't bring everything at once is beside the point. The programming 
model was 32 bit, which very significantly distinguishes it from the 
8086 architecture. Perhaps you want to call the 8088 an 8 bit 
processor?

8086: 16 bit registers, 16 bit data bus, 16 bit addressing with 
segmentation extensions.
8088: 16 bit registers, 16/8 bit data bus, 16 bit addressing with 
segmentation extensions.
68000: 32 bit registers, 32/16 bit data bus, 32/24 bit linear 
addressing.
68008: 32 bit registers, 32/8 bit data bus, 32/20-22 bit linear 
addressing.
(architecture/physical implementation)





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