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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,c30642befcd7bf85 X-Google-Attributes: gid103376,public From: ok@goanna.cs.rmit.EDU.AU (Richard A. O'Keefe) Subject: Re: Addresses of Subprograms (was: New GNAT ports) Date: 1997/01/14 Message-ID: <5bf9vc$220$1@goanna.cs.rmit.EDU.AU>#1/1 X-Deja-AN: 209684958 references: <5asvku$jtu$1@goanna.cs.rmit.edu.au> <32D2B847.6A7@lmtas.lmco.com> <5avfqo$it9$1@goanna.cs.rmit.edu.au> <1997Jan11.152602.1@eisner> <1997Jan13.102240.1@eisner> organization: Comp Sci, RMIT, Melbourne, Australia nntp-posting-user: ok newsgroups: comp.lang.ada Date: 1997-01-14T00:00:00+00:00 List-Id: kilgallen@eisner.decus.org (Larry Kilgallen) writes: [There is a distinction between the "address" of a subprogram, meaning "what do I use for an indirect call" and the "address" of a subprogram, meaning "where does the executable code start". He cites the Alpha VMS and Macintosh 68k environments as examples, and asks ] >Do other operating systems have this separation, and which is the >"true" meaning for specifying the address of a subprogram from an >Ada perspective ? The Apollo systems did this too. I never used Aegis, but the UNIX systems they shipped had C function pointers being pointers to indirect blocks, the actual code being elsewhere. It was actually a pain for us (Quintus) because we wanted to put a certain procedure at a particular address (so we could use 16-bit addresses on a 68k) and you could never expect a procedure to be in the same place twice running. Lisp systems have often done this (the "slow link" / "fast link" distinction) in order to support run-time redefinition of procedures. What do the Ada->J-code compilers do? -- My tertiary education cost a quarter of a million in lost income (assuming close-to-minimum wage); why make students pay even more? Richard A. O'Keefe; http://www.cs.rmit.edu.au/%7Eok; RMIT Comp.Sci.