Re: Internal sign encoding in DISPLAY and PACKED-DECIMAL usage

William,

Thank you for your answer and congratulation for your Faq: it is very
documented and interesting.

William M. Klein wrote:

>    You have mixed "apples and oranges" - although you may well be correct 
that
> there is an error in the documentation.
>
> What the Enterprise COBOL LRM states *is* true for the Enterprise COBOL
> compiler.
>
> It is *NOT* (always) true for IBM's COBOL for Windows.  The sign-nibble on
 the
> PC (with the IBM compiler - and several others) is the same between
> Packed-Decimal and Zoned Decimal when the compiler is in "EBCDIC" mode but
 IS
> not the same when in ASCII mode.

OK, I understand that. It is like in ASCII mode the DISPLAY sign
representation should be compatible with ASCII 7 bits (therefore lower
than 7F), while the PACKED sign representation need not to be
"printable" (ie it can be the same Ci, Di or Fi than in EBCDIC), isn't it ?

> Some compilers (for example Micro Focus) has an option for working in ASCI
I
> mode - but using EBCDIC sign-nibbles (or vice versa - I can't remember off
 the
> top of my head).  However, this is NOT true for the IBM Windows compiler.
>
> I don't see a separate web page for the "IBM Websphere Studio COBOL for Wi
ndows
> V5.11" manuals, but the VisualAge COBOL (predecessor product) is at:
>    http://www-306.ibm.com/software/awd...bol/va/library/

In fact, there is here:

http://www-306.ibm.com/software/awdtools/cobol/library/

You can find on this page two links regarding "COBOL for Windows", one
for Language Reference and the other for Programming Guide.

> and that seems to indicate that it uses the same LRM as the "mainframe"  (
older
> version IBM COBOL for OS/390 & VM) LRM.  If that is still the case with th
e
> current Windows compiler, then what you have found is a "bug".

Indeed there is now a separate LRM for Windows but it says exactly the
same thing regarding 4-bit sign representation (p.213). IMHO, this is at
least confusing...

I have another question about the sign position. I was thinking that the
default was TRAILING, but the IBM Websphere Studio COBOL PGM for Windows
V5.11 shows (p. 37 again) the following example:

For "PIC S9999 DISPLAY", the value -1234 is encoded like this (NATIVE):
71 32 33 34

For "PIC S9999 DISPLAY", the value -1234 is encoded like this (EBCDIC):
F1 F2 F3 D4

Therefore, in the first case, the sign seems to be held by the first
byte (71)... but I found no mention of this particularity. Do you have
an idea about that ?

Best Regards,

--
Vincent Danion.

The LRM seems to contradict the examples in the PG.  I have sent a query to 
one
of my "usually reliable sources" in IBM.

My *guess* is that it is the LRM that is wrong and that for some reason
WebSphere COBOL for Windows defaults to "leading" rather than trailing signs
.
If this is true, it would cause a medium serious "migration inhibitor" for
people trying to migrate existing IBM mainframe COBOL applications to that
environment  (as redefines that assume trailing are fairly common).

However, as I don't have the product myself, I'll wait to see what response 
(if
any) I receive.

--
Bill Klein
wmklein <at> ix.netcom.com
"Vincent Danion" <vdaNOniSPAMon@scort.com> wrote in message
news:300l0vF2q72joU1@uni-berlin.de...
> William,
>
> Thank you for your answer and congratulation for your Faq: it is very
> documented and interesting.
>
> William M. Klein wrote:
> 
>
> OK, I understand that. It is like in ASCII mode the DISPLAY sign
> representation should be compatible with ASCII 7 bits (therefore lower tha
n
> 7F), while the PACKED sign representation need not to be "printable" (ie i
t
> can be the same Ci, Di or Fi than in EBCDIC), isn't it ?
> 
>
> In fact, there is here:
>
> http://www-306.ibm.com/software/awdtools/cobol/library/
>
> You can find on this page two links regarding "COBOL for Windows", one for
> Language Reference and the other for Programming Guide.
> 
>
> Indeed there is now a separate LRM for Windows but it says exactly the sam
e
> thing regarding 4-bit sign representation (p.213). IMHO, this is at least
> confusing...
>
> I have another question about the sign position. I was thinking that the
> default was TRAILING, but the IBM Websphere Studio COBOL PGM for Windows V
5.11
> shows (p. 37 again) the following example:
>
> For "PIC S9999 DISPLAY", the value -1234 is encoded like this (NATIVE):
> 71 32 33 34
>
> For "PIC S9999 DISPLAY", the value -1234 is encoded like this (EBCDIC):
> F1 F2 F3 D4
>
> Therefore, in the first case, the sign seems to be held by the first byte
> (71)... but I found no mention of this particularity. Do you have an idea
> about that ?
>
> Best Regards,
>
> --
> Vincent Danion.