Re: What about big integers in Ada 2005?

[<adaworks@sbcglobal.net>]

"Dave Thompson" <david.thompson1@worldnet.att.net> wrote in message
news:bpujk1998r48p79n5jh1jtfgm42jl3ei8r@4ax.com...
> On Tue, 04 Oct 2005 18:56:20 GMT, <adaworks@sbcglobal.net> wrote:
> <snip>
> > BCD was originally a six bit (where 7 was a parity bit) representation.
With
> > the advent of the byte on the IBM System 360, BCD became Extended Binary
> > Coded Decimal Interchange Code (EBCDIC).
> >
> The 6-bit character code was BCDIC -- Binary Coded Decimal Interchange
> Code.  With the advent of _8-bit_ bytes on S/360 it became EBCDIC.
>
On the IBM 1401 and IBM 7080, we used the term Binary Coded Decimal
(BCD) for the six bit character.   BCDIC may have been the term on other
machines -- or perhaps we were simply using a short-cut name, but this
was how it was named in the IBM literature we were given.
>
> >
> > COMP-3 represented the numeric PICTURE by using a half-byte (nibble) for
each 9
> > in the picture and a nibble for the sign.   In the example shown, Hnumber
would
> > occupy
> > only three bytes where Number would occupy five bytes.   In both cases, the
> > high-order
> > nibble is used for the sign.
> >
> Not that last; the S/360 decimal instructions (AP, SP, etc.) put the
> sign in the low-order nibble, namely the low half of the highest
> addressed byte, which is the low-valued one on big-endian S/360.
>
Yes.  You are right.  It has been a long time since I have programmed
the S/360.   Now, do remember the bizzare format for a floating-point
number on the VAX.   I once had to convert VAX code to S/360 and
it was, at first, a bit of a nightmare.
>
Richard Riehle