From: Viqar Abbasi <viqar@cae.ca>
Subject: Fortran's Equivalence
Date: 1997/03/25
Date: 1997-03-25T00:00:00+00:00 [thread overview]
Message-ID: <333840D1.7B12@cae.ca> (raw)
Hi all...
Can anyone tell me the "standard" way to implement Fortran's
"EQUIVALENCE" in ADA? Okay, okay, I realize that this is not really
something that should be used in Fortran (or ADA) anyway. Still, I need
to do something as follows:
I have a BIT_PATTERN : System.Unsigned_32. The first 4 bits represent
an integer A, the next 17 represent another record B, the last eleven
represent an integer C. Ada gives something beautiful, in the "use at"
clause, which lets me define a record to superimpose onto the bit
pattern. The big problem with this approach is that it isn't
guaranteed by the LRM, and I need my application to be portable to
other Ada implementations. The Ada Quality and Style Guide, Clause
5.9.4, also tells us that we should not use the "use at" clause to do
such things. I am using the GNAT compiler, 3.07 on the SGI. The final
system will be delivered for a VAX.
I have started doing my mapping via "Unchecked Conversions". This seems
to be going well, as long as I take care of the VAX/SGI bit-pattern
differences. Would using Unchecked_Conversions, when the sizes are
always the same, be considered 100% portable, and will work under any
ADA implementation?
Furthermore, are any of you aware of a better way to map variables on
top of each other? Please consider in any reply that I have extremely
tight speed requirements as well.
Thank you kindly,
Viqar
next reply other threads:[~1997-03-25 0:00 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-03-25 0:00 Viqar Abbasi [this message]
1997-03-26 0:00 ` Fortran's Equivalence Tom Moran
1997-03-26 0:00 ` Michael F Brenner
1997-03-26 0:00 ` Larry Kilgallen
1997-03-28 0:00 ` Oliver Kellogg
1997-03-29 0:00 ` Matthew Heaney
1997-03-29 0:00 ` Robert Dewar
1997-04-01 0:00 ` Keith Thompson
1997-04-01 0:00 ` Robert Dewar
1997-04-01 0:00 ` Robert A Duff
1997-04-01 0:00 ` Robert Dewar
1997-04-04 0:00 ` Keith Thompson
1997-04-04 0:00 ` Keith Thompson
1997-04-04 0:00 ` Robert Dewar
1997-04-08 0:00 ` Keith Thompson
1997-04-04 0:00 ` Robert Dewar
1997-04-07 0:00 ` Keith Thompson
1997-04-07 0:00 ` Charles H. Sampson
1997-04-07 0:00 ` Viqar Abbasi
1997-04-08 0:00 ` Charles H. Sampson
1997-04-08 0:00 ` Matthew Heaney
1997-04-09 0:00 ` Stephen Leake
1997-04-09 0:00 ` Robert Dewar
1997-04-10 0:00 ` Simon Wright
1997-04-10 0:00 ` Robert Dewar
1997-04-08 0:00 ` Robert Dewar
[not found] ` <1997Apr15.163103.27481@nosc.mil>
1997-04-16 0:00 ` Robert Dewar
1997-04-07 0:00 ` Charles H. Sampson
1997-03-29 0:00 ` Robert Dewar
1997-03-26 0:00 ` Robert Dewar
1997-03-26 0:00 ` Robert A Duff
1997-03-29 0:00 ` Matthew Heaney
1997-03-29 0:00 ` Robert Dewar
1997-04-02 0:00 ` JP Thornley
1997-03-26 0:00 ` FORTRAN's Equivalence Nick Roberts
1997-03-28 0:00 ` Fortran's Equivalence Charles H. Sampson
1997-03-29 0:00 ` Matthew Heaney
1997-04-01 0:00 ` Charles H. Sampson
1997-03-29 0:00 ` Matthew Heaney
1997-03-29 0:00 ` Robert Dewar
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