Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!rutgers!apple!vsi1!wyse!mips!mash From: mash@mips.COM (John Mashey) Newsgroups: comp.arch Subject: Re: Not-so RISCy Keywords: risc Message-ID: <13584@winchester.mips.COM> Date: 19 Feb 89 23:50:43 GMT References: <732@wpi.WPI.EDU> <13259@winchester.mips.COM> <483@eutrc3.UUCP> Reply-To: mash@mips.COM (John Mashey) Organization: MIPS Computer Systems, Sunnyvale, CA Lines: 32 In article <483@eutrc3.UUCP> rcbaps@eutrc3.UUCP (Pieter Schoenmakers) writes: >In article <13259@winchester.mips.COM> mash@mips.COM (John Mashey) writes: >>[...] I wouldn't put UNIX on a machine >>that didn't have 16-bit operations, even though many user-level statistics >>wouldn't justify their presence. [...] > >Just for your information: it has been done: the Acorn Archimedes R140, >which is to be released officially this month, runs Unix BSD on the ARM, >a load/store RISC processor, supporting only 32 bit operations on registers >and having word (32bit) and signed char (8bit) load/store operations. > I don't have any benchmarks on the Unix version, but the C compiler I have >on my Archimedes warns about the use of shorts (ansi! :), but is _very_ fast >for a desktop computer running at a mixture of 4 and 8 Mhz (Dhrystone results >put it just below an IBM PS2/80). Oops, I should I have been more specific. Not having anything but 32-bit arithmetic doesn't bother me (or most of the other RISC types), but I care about 16-bit loads and stores both for performance reasons, and for the sturctural reason of dealing cleanly with 16-bit device registers from arbitrarily-chosen peripheral boards. UNIX certainly can be put on a machine without 16-bit load/stores, and has been put on far uglier machines, and for some implementations it might well be the least of evils to leave out halfword operations. [Note, or course, that Dhrystone doesn't use halfwords in any significantly noticable numbers...] Anyway, I didn't mean to imply that it was impossible to put UNIX on such a machine, merely that *I* wouldn't do it! -- -john mashey DISCLAIMER: UUCP: {ames,decwrl,prls,pyramid}!mips!mash OR mash@mips.com DDD: 408-991-0253 or 408-720-1700, x253 USPS: MIPS Computer Systems, 930 E. Arques, Sunnyvale, CA 94086