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From: bobduff@world.std.com (Robert A Duff)
Subject: Re: Waiver question
Date: 1997/05/03
Message-ID: <E9KxAK.IyC@world.std.com>#1/1
X-Deja-AN: 238994299
References: <dewar.861594356@merv> <1997May2.063334.1@eisner>
 <E9KA78.DxH@world.std.com> <1997May2.164921.1@eisner>
Organization: The World Public Access UNIX, Brookline, MA
Newsgroups: comp.lang.ada
Date: 1997-05-03T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <1997May2.164921.1@eisner>,
Larry Kilgallen <kilgallen@eisner.decus.org> wrote:
>A casual programmer would presume that if variable A is only modified
>by task AA and variable B is only modified by task BB then they are
>task-safe.  This is not true if the variables share a longword on
>Alpha.  Having variables default to not sharing a longword goes a
>long way toward eliminating this exposure.

OK, but remember that we're only talking about subcomponents of the same
record or array, here.  Two different object declarations always produce
independently addressable objects -- it's just a question of whether X.A
and X.B are independently addressable (which currently depends on
whether the type of X is packed).

>Regarding Robert Dewar's comment about DEC changing their mind
>with regard to byte instructions, I believe that was driven by
>the need to emulate code compiled for Intel machines which had
>never gotten recompiled specifically for Alpha.  Market realities,
>rather than machine efficiency are at play.

Maybe DEC wanted to be Ada-friendly.  ;-)

- Bob