From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,2a34b7ad6c6a0774 X-Google-NewGroupId: yes X-Google-Attributes: gida07f3367d7,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news2.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.bt.com!news.bt.com.POSTED!not-for-mail NNTP-Posting-Date: Sat, 14 Aug 2010 19:50:50 -0500 From: Brian Drummond Newsgroups: comp.lang.ada Subject: Re: Efficiency of code generated by Ada compilers Date: Sun, 15 Aug 2010 01:58:17 +0100 Reply-To: brian@shapes.demon.co.uk Message-ID: References: X-Newsreader: Forte Agent 1.7/32.534 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Usenet-Provider: http://www.giganews.com X-AuthenticatedUsername: NoAuthUser X-Trace: sv3-ngcdCDxJajAyliBGyzR+Kq4VaazWjq+G2/a+9PGyPnJn9/AlVoAgCQnLDGAyXp1lDDaqq4O+Za9B8fr!ZkYtyQoLOYxRRY5mhW4bHlTNsBB7bf35cBWpozw+RKd9O6Lwy3eqobZ04+DHsZep7YCdwKMDG3Z4!k8w= X-Complaints-To: abuse@btinternet.com X-DMCA-Complaints-To: abuse@btinternet.com X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Xref: g2news1.google.com comp.lang.ada:13313 Date: 2010-08-15T01:58:17+01:00 List-Id: On Sat, 14 Aug 2010 15:51:15 +0100, "(see below)" wrote: >On 14/08/2010 11:47, in article jvqc66t42m4ek5rkpj59ctu3r75fb4hln2@4ax.com, >"Brian Drummond" wrote: > >> I was involved with the Linn Rekursiv processor (which I'm sure at least two >> other group regulars remember) > >Indeed. Though David Harland's ideas on programming language design were >about as far removed from the Ada philosophy as it is possible to get. I'm not so sure on *design* - the goals were largely to achieve expressive power, to give the programmer the best abstractions; the best means of expressing the task, instead of working around the limitations of the language. I was reminded today of his insistence there should be no difference between intrinsic and extrinsic notation today, when I made a record "private" and replaced all its field accesses with accessor functions - and because the syntax was the same, the client code worked unchanged. So I suggest there is at least some common ground. But on *implementation*, or the route to achieving those goals; absolutely! Everything was to be done at runtime, by the hardware, rather than at compile time. Including strict typing, or indeed any typing at all! And with _some_ justification - an Ada compiler at the time was not a trivial task, to write or even to run... while the compilers of his were simple in the extreme, ultimately supporting a language (called Lingo, long before Macromedia borrowed the name) with a very compact grammar. This could be compiled to an instruction set of eleven instructions. I won't claim any great merit in that simplicity, but it did allow a team of six or seven people at its largest to develop the whole lot; from compilers through microcode to chipset to circuit board. I wonder how many people worked on Ada... >> There was much talk then of "bridging the semantic gap" between high level >> languages and the low level operations in hardware. It seems we have >> subsequently bridged the semantic gap, by leaning to program in C... (ack! should have read: learning to program in C) >One of our subject's many self-inflicted tragedies (c.f. the apparently >pervasive ignorance about the Burroughs architecture). I never had the chance to work on those, though I remember lectures on them. Perhaps we need a Burroughs B5000 emulator; it would probably fit on a medium-sized Spartan-3 FPGA... - Brian