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Date: 23 Jul 93 19:15:47 GMT
From: telesoft!garym@uunet.uu.net  (Gary Morris @ignite)
Subject: Re: Forcing default representations
Message-ID: <1993Jul23.191547.21281@alsys.com>
List-Id: <comp.lang.ada>

In <9307221834.AA03070@eight-ball.boeing.com> crispen@eight-ball.boeing.com (Bo
b Crispen) writes:
>By the way, here's a semi-trivial question:  Does anyone know of
>a real Ada compiler that doesn't assign internal values of integers
>(forget the size for a minute) beginning with zero as a default for
>enumerations?  

I suspect all compilers would assign internal values that match the
position number, doing something different would impact the performance
of the 'pos operation since the position number is required to start at
zero (LRM 3.5.1 p4).

The only exception I've ever seen was a TeleSoft compiler that used internal
values of 0 and -1 for Boolean, with the corresponding position numbers of 0
and 1.  This was for a MC680X0 processor and boolean operations were more
efficient by making True have an internal value of -1. 

--GaryM
-- 
Gary Morris                      Internet: garym@alsys.com
TeleUSE/Ada Development          UUCP:     uunet!alsys.com!garym
Alsys Inc. (TeleSoft)            Phone:    +1 619-457-2700 x128
San Diego, CA, USA               Fax:      +1 619-452-1334