Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site noscvax.UUCP Path: utzoo!decvax!tektronix!hplabs!sdcrdcf!sdcsvax!noscvax!broman From: broman@noscvax.UUCP (Vincent P. Broman) Newsgroups: net.lang.mod2 Subject: what is a WORD? Message-ID: <1075@noscvax.UUCP> Date: Tue, 20-Aug-85 12:32:43 EDT Article-I.D.: noscvax.1075 Posted: Tue Aug 20 12:32:43 1985 Date-Received: Sat, 24-Aug-85 05:46:19 EDT Distribution: na Organization: Naval Ocean Systems Center, San Diego Lines: 24 Xref: tektronix net.lang.mod2:00245 <> The explanation of WORD and ADDRESS in Wirth's "Programming in Modula-2" has produced fog and confusion in me. I wonder whether someone who has worked with an Actual Implementation (I haven't) could shine a light. Wirth implies repeatedly that contiguous WORDs have consecutive ADDRESSes, for instance in his code on p127 he increments an ADDRESS by 1 to access the next WORD. Since many machines are byte-addressed, this seems to imply that these would also have WORD=byte. On the other hand, the impression is given that a WORD is the natural access unit of the machine, and says on p126 "On the PDP-11, TSIZE(WORD)=2, since the addressable unit of store is the byte" (even though TSIZE really counts WORDs). Should a VAX get 4-byte WORDs? Also, if ADDRESSes are usable as CARDINALs for arithmetic, is this hard to do on the 8088 family, with 16-bit integers and 20-bit addresses? I suppose the Turbo Modula coming out now will only implement a small memory model, avoiding the problem, but do Logitech and the others implement it with long CARDINALs? UUCP: ucbvax!sdcsvax!noscvax!broman Vincent Broman ARPA: broman@nosc Naval Ocean Systems Center, code 632 Phone: (619) 225-2365 San Diego, CA 92152