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=1.9 required=5.0 tests=BAYES_50,INVALID_DATE, MSGID_SHORT autolearn=no autolearn_force=no version=3.4.4 Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!uflorida!novavax!augusta!bs From: bs@augusta.UUCP (Burch Seymour) Newsgroups: comp.lang.ada Subject: Rep Specs - Need user input Keywords: bits, small fields, speed, Ada Message-ID: <1291@augusta.UUCP> Date: 19 Sep 88 19:30:40 GMT Organization: Gould CSD, Fort Lauderdale, FL List-Id: I would like to hear from Ada users (by e-mail preferred, I'll post summary if enough response) about their use and expectation of rep-spec implementations. The basic problem from my point of view (working on the Ada runtime library) is that it is a non-trivial problem to manipulate non-byte multiple data items with an instruction set that deals with byte, 2 byte, 4 byte, and 8 byte items. A simple Ada instruction such as x := 5; where x is a rep spec'd item of, say, 17 bits, causes a call to a library routine which has to do a lot of masking and shifting to generate the result. The question then is, how important is eeking the last bit of speed out of rep specs? Or are people just doing conversions to/from more conventional data representations and doing the speed critical stuff with those items? Any thoughts on these questions, other Rep Spec issues, or performance in general would be appreciated. You can try the following mail paths, we've been disconnected from the net for a while due to modem problems at our feed, but I think my dot sig file is still mostly correct. Thanks, -------------------------------------------------------------------------------- ##### Gould Computer Systems Division ### in Sunny South Florida ##### ##### Burch Seymour ##### #### => ...!{uunet,sun,pur-ee,brl-bmd}!gould!bseymour ##### ##### => ...!{ihnp4!codas,allegra}!novavax!gould!bseymour ## => NOTE: Disregard header info. Email to above paths only. #### => The opinions expressed are probably not worth disclaiming ================================================================================