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From: "Robert I. Eachus" <eachus@mitre.org>
Subject: Re: Why Ada is not the Commercial Lang of  Choice
Date: 1997/06/18
Date: 1997-06-18T00:00:00+00:00	[thread overview]
Message-ID: <33A7FBFF.29D2@mitre.org> (raw)


Paul Van Bellinghen writes:
> 
> Claim:
> It is much easier in C, for example, to output a data word to
> an I/O device that is memory mapped.
> 
> Supporting Evidence:
> 1       One need only define a pointer
> 2       and assign it the memory mapped address
> 3       then store the desired data value to the contents of the pointer.
> 
> Example:
>  #define mem_map_addr B0100040
>  unsigned int *p;
> 
>  p = (unsigned int *) mem_map_addr;
> 
>  *p = 0x00344556;
> 
> Claim:
> It is harder to do it in Ada because i write it out in more words.

   Wait a second here.  The eqivalent Ada is:

   Mem_Map: Integer;
   for Mem_Map'Address use 16#B0100040#;
 begin
   Mem_Map := 16#00344556#;

   ...which is a little shorter in terms of characters, words, and
lines.  I could go into the bugs in both the Ada and the C--I'd want
pragma Volitile(Mem_Map); in both Ada and C.  Most compilers will get it
"right" but why take the risk.  Also, it might be necessary to call
System.Storage_Elements.To_Address, but I can't imagine any compiler for
a machine where 16#B01000040# is a meaningful address not allowing
literals for addresses.

-- 


                                               Robert I. Eachus

with Standard_Disclaimer;
use Standard_Disclaimer;




             reply	other threads:[~1997-06-18  0:00 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1997-06-18  0:00 Robert I. Eachus [this message]
1997-06-18  0:00 ` Why Ada is not the Commercial Lang of Choice Dale Stanbrough
1997-06-19  0:00   ` Steve Jones - JON
1997-06-19  0:00     ` Peter Hermann
1997-06-19  0:00     ` Anonymous
1997-07-17  0:00     ` Shmuel (Seymour J.) Metz
1997-06-19  0:00   ` Robert A Duff
1997-06-21  0:00     ` Paul Van Bellinghen
1997-06-20  0:00       ` Robert Dewar
1997-06-23  0:00         ` John G. Volan
1997-07-03  0:00           ` Shmuel (Seymour J.) Metz
1997-07-03  0:00             ` Robert Dewar
1997-07-06  0:00               ` Yasmiin S. Davis
1997-07-06  0:00                 ` Robert Dewar
1997-07-07  0:00               ` Shmuel (Seymour J.) Metz
1997-07-04  0:00             ` Paul Van Bellinghen
1997-07-13  0:00               ` Ken Mays
1997-07-13  0:00                 ` Robert Munck
1997-07-14  0:00                   ` Ken Mays
1997-06-20  0:00   ` Don Harrison
1997-06-20  0:00     ` Roy Grimm
1997-06-20  0:00     ` Donovan Baarda
1997-06-20  0:00     ` Larry Kilgallen
1997-06-20  0:00       ` Nick Leaton
1997-06-23  0:00       ` Don Harrison
1997-06-24  0:00         ` Bertrand Meyer
1997-06-24  0:00           ` Nick Leaton
1997-07-22  0:00           ` Dr. Vladimir Il'ich Fomin
1997-06-23  0:00     ` Joachim Durchholz
1997-06-23  0:00     ` Robert Dewar
1997-06-24  0:00       ` Don Harrison
1997-06-24  0:00         ` Robert Dewar
1997-06-20  0:00   ` Robert Dewar
1997-06-20  0:00 ` Robert Dewar
1997-06-21  0:00 ` Keith Thompson
1997-06-21  0:00   ` Robert Dewar
1997-06-24  0:00     ` Ken Garlington
1997-06-24  0:00       ` Robert Dewar
1997-06-28  0:00   ` Robert I. Eachus
1997-06-28  0:00     ` Robert Dewar
  -- strict thread matches above, loose matches on Subject: below --
1997-06-13  0:00 Paul Van Bellinghen
1997-06-17  0:00 ` Dale Stanbrough
1997-06-17  0:00   ` Robert Munck
1997-06-18  0:00   ` Ken Garlington
1997-06-19  0:00     ` Ole-Hjalmar Kristensen FOU.TD/DELAB
1997-06-19  0:00       ` Ken Garlington
1997-06-17  0:00 ` Robert Dewar
1997-06-20  0:00   ` nma123
1997-06-24  0:00     ` Adam Beneschan
1997-06-18  0:00 ` Nick Roberts
1997-06-18  0:00   ` Peter Hermann
1997-06-20  0:00     ` Robert Dewar
1997-06-25  0:00     ` Van Snyder
1997-06-26  0:00       ` Robert Dewar
1997-06-30  0:00         ` Ralph Paul
1997-07-02  0:00           ` Joerg Rodemann
1997-07-02  0:00             ` Ralph Paul
1997-07-02  0:00             ` Joerg Rodemann
1997-06-19  0:00 ` Steve Doiel
1997-06-19  0:00   ` Anonymous
1997-07-22  0:00 ` Shmuel (Seymour J.) Metz
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