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This is a classic dispute when it comes to the 68000. I'm inclined to agree with your perspective, actually, but my impression is that it's highly contested. C
by wk_end 6mo ago
This is a classic dispute when it comes to the 68000. I'm inclined to agree with your perspective, actually, but my impression is that it's highly contested.
Commodore and Atari marketed their 68K machines as 16/32-bit, which is I guess technically the most correct. And other 68000-based machines, like the Sega Mega Drive/Genesis, were marketed as 16-bit - it even says it right on top of the unit!
- vidarh 6mo agoYeah, I second that 16 bit or 16/32 was far more commonly used than 32, due to the 16 bit bus.
- kstrauser 6mo agoThe bus always seemed like the oddest part to zero in on. By analogy, an Opteron in 2003 was a 64 bit CPU with a 32 bit HyperTransport bus, but no one called an Opteron system 32 bit. The width of a particular internal implementation detail is a strange duck IMO.
- wk_end 6mo agoI think part of it was that to hardware companies the bus width is actually extremely important - the whole system is built around it, and the programming model the software guys work with less so. And then the other part of it is the marketing angle: everyone knew full 32-bit inside and out chips were just on the horizon. Downplaying the 68k’s 32-bitness would give them a selling point for the 68020.
- feffe 6mo agoAll ALU operations are also more expensive with 32 bit operands. So 16 bit data bus, 24 bit address bus. Slower arithmetic with 32 bit operands. I never though of it as a 32 bit CPU.