hardware multiply/divide functionality in CPUs

Jules Richardson jules.richardson99 at gmail.com
Mon Mar 7 17:49:20 CST 2011

Tony Duell wrote:
> What do you mean by 'hardware' multiply and divide? A number of machines, 
> I suspect the 6809 is amongst them, had no particualrl hardware for 
> multiply or divide, but they did have multiply and maybe divide 
> instrucitons in the instruction setc. These instrucitons were implemented 
> by microcode using the normal registers and ALU. Does that count?

Yes, anything that includes a dedicated multiply or divide instruction as part 
of the instruction set; I suspect a lot of the early implementations fall into 
the "simple shift-add" that I mentioned due to the lack/cost of silicon.



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