Re: matpg, odv, oes encoding

Visual inspection of the ODV and OES strings in the MI compile listing show
that data objects with addressability other than AUTO and STAT contain a 2
byte offset in pos(3-4) of the ODV. This offset points to the extended OES
encoding of the data object.

Searching the archives on this subject returned a post that quotes Dr Frank
saying that the increase from 2 byte to 3 byte operands enabled many more
data objects in a pgm.

But the 4 byte size of the ODV entry and the 2 byte only offset to the OES
looks to be unchanged in a 3 byte operand size pgm. And the MATPG template
does not contain a fld that sets the size of the ODV entry. So the size of
an OPM pgm looks like it is limited by the capacity of this 2 byte offset.
( offset, not an index ).

Steve Richter


----- Original Message -----
From: "Leif Svalgaard" <leif@leif.org>
To: <mi400@midrange.com>
Sent: Tuesday, November 06, 2001 11:15 AM
Subject: Re: [MI400] matpg, odv, oes encoding


> From: Steve Richter <srichter@AutoCoder.com>
> Are the encoding schemes of the ODV and OES entries in the MATPG template
> known?
>
> ===> the short answer is yes. The S/38 functional reference manual section
8
> explains the precise structure of a program template.
>
> I dont have a pressing need for this right now, but you can enhance the
> MATINAT and QTERTVPV api if the data defn of an ODVN can be materialized.
>
> What do we call the 2 byte index into the ODV that, when expressed in hex
> external form, is used to identify data objects in the MI pgm. On the
AddBkp
> cmd, the system refers to it as "machine-interface
> object-definition-table-vector (MI ODV) number". ODVN? ODTN?
>
> ===> The template has three pieces:
> 1) the template definition containing things like name, version,
authority,
> ...
> 2) the instruction stream
> 3) the Object Definition Table (ODT).
>
> The ODT in turn consists of
> a) the Object Directory Vector (ODV)
> b) the Object Entry Strings (OES)
>
> The index into the ODV is called the ODT Reference Number.
>
> Some of this has undoubtedly evolved with time.
>
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