Re: How does Alsys index bit-arrays on Intel ?

[strohm@mksol.dseg.ti.com (john r strohm)]

In article <C4CLou.I5z@watson.ibm.com> ncohen@watson.ibm.com describes an
Ada algorithm to determine which bit (most or least significant) is numbered
how.

The problem is that this tells only how that particular version of that
particular compiler for that particular host and target numbers them.  This
does NOT give any assurance that a compiler from a competing vendor will
do the same thing, nor does it even cover the case of another compiler from
the same vendor, for the same host but a different target, or even (in a
REALLY baroque scenario) for a subsequent release of the SAME compiler.
The language of the standard allows the vendor to do what he/she wishes.

This, in my personal opinion, is one of the few places where Ada goofs.

Now, the flip side is that there is a good argument for making it
implementation-dependent.  Some machines still number bits left-to-right,
while others number right-to-left, and we still have Endian problems
every time we change processors (almost).  Choosing one scheme and
enforcing it is going to cause major heartburn for SOMEBODY, as they
curse the standard because none of their databooks are useable: they
all have the bits numbered backwards.