Re: GNAT 4.4.5 Record Bit_Order Endian issues

["J-P. Rosen" <rosen@adalog.fr>]

Le 17/01/2013 23:16, awdorrin a �crit :
> This is why I thought the Bit_Order flag was used to fix.
> On Intel, using Bit_Order = System.High_Order_First,
> I would have expected to see: 0xcb 0xa0
I didn't follow the discussion closely, but from this remark it seems
you are confusing bit order and byte order.

High_Order_First is only about bit order, i.e. whether, in a 32 bits
value f.e., the leftmost bit is numbered 31 or 0. It has nothing to do
(and no effect) on the order in which the various bytes that make up
this value are stored in memory.

Regarding the use of "at": you can always use 0 and number the bits
starting from the beginning of the record (and bit numbers are not
limited to 31). "at" just saves you a multiplication by the number of
bits in a storage unit. It is there because you normally use
representation clauses in connection with some low level device, and the
idea was to allow to copy directly from your hardware reference manual,
using the same description.

-- 
J-P. Rosen
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