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That is an odd case.

I'd still call it a 32-bit CPU as it had 32-bit registers and instructions (and not just a few special case 32-bit instructions IIRC). Like the 386SX it had a 16-bit external data bus, but some of its internal data routes were 16-bit also (where the 386SX had the full 32-bit core of a 386, later renamed 386DX, with the changes needed to change the external data bus) as were some of its ALUs hence the confusion abaout its bit-ness.

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In a way, the fact that you have home computer market calling it 16bit, while at the same time you have workstation systems that plainly talk about 32bit ISA, shows how much of marketing issue it is :)

Would you call the 6809 a 16 bit device?

I'm not aware of that one off the top of my head. If it naturally operated over 16-bit values internally (i.e. it had 16-bit registers and a primarily 16-bit¹ instruction set), at least as fast as it could work with smaller units, then probably yes.

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[1] So not a mostly 8-bit architecture with 16-bit add-ons. The 8086 had a few instructions that could touch 32 bits, multiply being able to give a 32-bit output from two 16-bit inputs for instance (though the output was always to a particular pair of its registers), but a few special cases like that doesn't count so it is definitely 16-bit.

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