Re:Arithmetic in Computer Hardware
by kyboren on Friday November 17, 2023 @05:54PM
(#38311764)
> So once we have a full adder, all we need to do for multiple bits is to chain a whole bunch of them together!
Heh. I'm not sure if this is a joke or an intentional oversimplification, but the design space for adders is pretty large, and there are all sorts of interesting adder architectures. The author describes what's called a "ripple carry" adder, which is perhaps the conceptually simplest adder, and is very efficient in logic area but very slow.
Modern adders in your M2 Pro are (just guessing) probably a much more interesting hybrid parallel-prefix adder architecture (e.g. part Kogge-Stone, part Brent-Kung, part Carry-Select or Ripple-Carry) that sits directly on the multidimensional Pareto frontier for delay/area/power.
Heh. I'm not sure if this is a joke or an intentional oversimplification, but the design space for adders is pretty large, and there are all sorts of interesting adder architectures. The author describes what's called a "ripple carry" adder, which is perhaps the conceptually simplest adder, and is very efficient in logic area but very slow.
Modern adders in your M2 Pro are (just guessing) probably a much more interesting hybrid parallel-prefix adder architecture (e.g. part Kogge-Stone, part Brent-Kung, part Carry-Select or Ripple-Carry) that sits directly on the multidimensional Pareto frontier for delay/area/power.