
Ask HN: Why do computers use a fixed word size? - mkeyhani
Also, are there any advantages to implementing arbitrary-precision arithmetic at a hardware level?
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CyberFonic
When you look at the design of the hardware, the various busses and registers
are of a fixed maximum size. For example, small micro-controllers might have 8
bit registers and data busses and 16 bit address busses. This in turn means
that the arithmetic unit processes information at that chunk size. There have
been attempts at variable word size architectures (especially in the early
days) but the amount of circuitry required to marshall variable sized
information in and out of fixed sized hardware resources became excessive.
Similar concerns apply to arbitrary-precision FPUs. These architectural
concerns then propagate to the cache designs, memory and and I/O channels.

Of course, these concerns only apply at the hardware level. There are virtual
machines, e.g. Lisp systems, that implement variable sized operations.

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chaggy
as far as the "arbitrary precision" arithmetic, no.

