Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!henry From: henry@utzoo.UUCP (Henry Spencer) Newsgroups: net.micro Subject: Re: 4->8->16->32->64? bit micros Message-ID: <4845@utzoo.UUCP> Date: Sat, 29-Dec-84 20:17:51 EST Article-I.D.: utzoo.4845 Posted: Sat Dec 29 20:17:51 1984 Date-Received: Sat, 29-Dec-84 20:17:51 EST References:<280@oakhill.UUCP> <256@tekigm.UUCP>, <274@desint.UUCP> Organization: U of Toronto Zoology Lines: 19 The question is not whether 64-bit numbers have uses, but whether they have enough uses to justify the costs of making them all-pervasive. The arguments for having them seem significant, but the arguments for making them the basic type seem weak. Note that 16 bits is in fact enough for a lot of variables, if 32 is available for the exceptions; the push from 16 to 32 came from addresses, not data. Whether we will eventually start to find 32-bit addresses confining is an interesting question. (Except in specialized areas where it's a foregone conclusion, like bulk number-crunching -- *those* machines have had monster address spaces for quite a while.) It is clear that 32 bits will suffice for the next little while; whether the past growth in space requirements will continue past 32 is harder to predict. It might. An interesting sidelight on this: if you're wondering why the 68000 has that silly separation between A and D registers, it's because the first 68000 design had 16-bit D registers but bigger A registers. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry