METHOD FOR CONVERTING DIFFERENT DATA FORMATS

PROCEDE DE CONVERSION DE FORMATS DE DONNEES DIFFERENTS

English Abstract

Current multi-processor systems, such as communication systems, are generally
provided with processors for processing various data formats. The information
exchanged between such processors must therefore be submitted to a format
conversion. The state-of-the-art techniques involve heavy operations in the
compiler or a standardised data format in the interface (e.g. ASN.1) in order
to reach this goal. The present invention provides a more efficient method
that involves using a tool for automatically introducing a conversion process
in the software interface between the processors.

French Abstract

Les systèmes multiprocesseurs actuels tels que par ex. les systèmes de communication sont en règle générale équipés de processeurs qui traitent des formats de données divers. Des informations qui sont échangées entre des processeurs de ce type doivent donc être soumises à une conversion de format. Dans l'état actuel de la technique, des interventions importantes dans le compilateur ou un format de données standardisé dans l'interface (par ex. ASN.1) sont nécessaires à cet effet. Selon la présente invention, une procédure plus efficace est obtenue grâce à la présence d'un outil à l'aide duquel une procédure de conversion est introduite automatiquement dans l'interface logicielle entre les processeurs.

Claims

Patent claims
1. Method for converting different data formats in a multiprocessor system,
having at least two processors (P1, P2), on which application programs having
data of
differing formats are respectively processed, and between which an interface
(S) is arranged,
and between which messages (N) are exchanged under the control of a
communication
handler (KH), whereby the message (N) of the transmitting processor (P1) is
converted into
the format of the processor (P2) receiving the message (N),
characterized in that
before the commissioning of the multiprocessor system a tool is controlled by
means of
which, according to the definition of the interface (S) stored in the data
layout, a conversion
procedure (UP) for the conversion of the data formats is produced and is
linked as a part of
the communication handler (KH).
2. Method according to claim 1,
characterized in that
the conversion procedure (UP) is produced on the source code plane, and in
that
in a subsequent compiler run the application programs are translated together
with the
conversion procedure (UP) [or: are translated together, using the conversion
procedure]
and are linked into the communication handler (KH) using a linkage [or:
connective]
program.
3. Method according to claim 1, 2,
characterized in that
the communication handler (KH) is an integral component of the interface (S).
4. Method according to claim 1 to 4,
characterized in that
first a message (N) is handed over by the sending processor (P1) to the
communication
handler (KH), where an evaluation of the data format of the sending processor
(P1) and of the
receiving processor (P2) is carried out,

and in that a conversion of the data format of the message (N) into the data
format of the
processor (P2) receiving the message (N) is carried out, and in that
the message is supplied in this format to the receiving processor.

Description

CA 02340708 2001-02-15
Specification
Method for converting different data formats
The invention relates to a method according to the preamble of patent claim 1.
Modern communication systems are fashioned as multiprocessor systems. This
means that
the controlling of the system-internal processes is carried out by a
multiplicity of processors.
As a rule, such communication systems are fashioned as heterogeneous systems.
This means
that processors of various manufacturers are used in the communication system.
However,
these processors thereby also operate according to manufacturer-specific
standards. Thus, for
example, data of the individual processors are stored in different formats in
the respectively
allocated memory. This does not result in a limitation of operation as long as
programs,
which as a rule are respectively allocated to one processor during their
execution, read these
data from the relevant memory, process them, and write them into the memory
again, since in
this case the same data format is always used. Problems most often arise when
messages or
data are exchanged between processors or, respectively, between programs
running on these
processors, because here, if necessary, these data must be adapted to the
different data
formats.
Thus, for example, data that are processed on processors of the Motorola
family are stored by
these processors in a LSB HI format (Least Significant Byte at Highest
Address), also known
as the Big Endian format. In contrast to this, data that are processed on
processors of the
Intel family are stored by these processors in a LSB LO format (Least
Significant Byte at
Lowest Address), also known as the Little Endian format. For this reason, in
the case of a
data exchange between these two types of processors the data have to be
converted
correspondingly.
For the solution of such problems with respect to different data formats in
process
communication in heterogeneous systems, in the prior art a specific transfer
format is defined
for the exchange of messages and data (e.g. ASN.1 ). This means that in
general before every

CA 02340708 2001-02-15
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exchange of messages the processor-specific format is converted into a
previously defined
transmission format used only for the purpose of the exchange of messages.
Once the
message has arrived at the target processor, the transmission format is
converted back into the
processor-specific format used there.
A problematic feature of such a procedure is that the programs that
communicate with one
another via the exchange of messages are each themselves responsible for the
conversion of
the messages to be exchanged between the processor-specific data format and
the transfer
format. However, all required format conversions must thereby be programmed
explicitly by
the developer of the application software in the coding of the respective
program. In
addition, in the use of this transfer format a total of two conversions must
be carried out,
namely on one hand a conversion of the format from the source processor into
the transfer
format, and from this format back into the format of the target processor.
Because, due to its
structure, the transfer format is very extensive, the dynamics of the system
is thereby
adversely affected. Finally, with the strict application of this technique
there is the problem
that conversions from the processor-specific data format of the source
processor into the
transmission format and from the transmission format into the processor-
specific data format
of the target processor take place even given the sending of messages between
programs that
run on processors having one and the same data format. This has a further
adverse effect on
the dynamics of the system.
In addition, in the German patent application 19535306.4 a method is specified
for the
conversion of differing data formats with which messages are exchanged between
processors
on which different data formats are respectively used. For this purpose, the
procedures
required for the conversion of the data between the formats are already
provided
automatically during the translation process of the source programs. This is
achieved in that
the translation program, in accordance with the data types used in the source
programs,
produces conversion procedures during the course of the translation that are
then called
during the later execution of the translated programs, before the exchange of
messages.

CA 02340708 2001-02-15
However, a problematic feature of such a procedure is that extensive
interventions in the
compiler must be carried out. For this purpose, detailed knowledge of the
compiler is
necessary, which makes this process expensive and uneconomical for the user.
The invention is based on the object of indicating a way in which the
conversion of data
formats can be controlled more efficiently without having to accept the
disadvantages cited
above.
In particular, an advantage of the invention is that before the commissioning
[or: startup] of
the multiprocessor system a tool is controlled by means of which, according to
the definition
of the interface stored in the data layout, a conversion procedure for the
conversion of the
data formats is produced, and in that, in a subsequent compiler run, the
application programs
are translated together with the conversion procedure [or: are translated
together using the
conversion procedure] and are linked in a linkage editor as a part of the
communication
handler. A conversion machine is thereby produced in fully automatic fashion
from the
interface definition. The required conversion is thereby carried out
automatically during the
exchange of messages.
The data structures can be transmitted in their original form, that is,
without additional format
information. In this way, a significantly higher level of performance is
achieved. For this
purpose, it is necessary that the source code of the data structures be known
both to the
sending and to the receiving processor.
Advantageous developments of the invention are indicated in the subclaims.
The invention is explained in more detail in the following on the basis of a
graphically
depicted exemplary embodiment.
According to the figure, as an example two processors P" P2 of a multiplicity
of processors of
a multiprocessor system are indicated. On both processors, programs are
provided for
execution that carry items of information and data having differing formats.
For example, it

CA 02340708 2001-02-15
4
is assumed that data in the Big Endian format are carried and processed on the
processor P,.
In contrast, assume that data in the Little Endian format are carried on the
processor PZ.
Therefore, in the case of an exchange of data between these two types of
processors the data
to be exchanged must be converted in a corresponding manner. The conversion is
thereby
preferably to take place by means of a conversion procedure UP executed on the
processor P,
In addition, an interface S is arranged between the two processors P" P2. This
interface
represents a software interface between the programs running on the two
processors. The
interface S is to be defined upon commissioning of the system, which
definition takes place
via the corresponding data layout for this interface. In the data layout, it
is defined which
programs communicate with one another during the execution and which data
types are
carried in these programs. In addition, a communication handler KH, which
controls the
exchange of messages between the two processors, is arranged in the interface
S.
According to the invention, a tool is provided that stands in effective
connection with a
compiler. The compiler is assumed to be a standard commercially available
compiler. The
tool is started during the production of the software for the processor P,. In
the tool,
according to the definition stored there in the data layout, the conversion
procedure UP is
produced on the source code plane. As a result, the conversion procedure UP
becomes
independent of the compiler used and is simple to implement. In the subsequent
compiler
run, the programs are translated together with the conversion procedure UP
(or: are
translated together, using the conversion procedure] and are linked in the
linkage editoi as
a part of the communication handler ICH. These actions are to be carried out
before the
commissioning of the multiprocessor system.
In the following, during running operation a message N is to be sent from the
processor P, to
the processor Pz. For this purpose, the processor P, first hands over the
message N to the
communication handler KH. There the format of the message N is determined and
is
converted, by the conversion procedure UP implemented there, into the target
format of the
processor P2. The conversion takes place automatically via the conversion
procedure UP,

CA 02340708 2001-02-15
without the piogrammer's having to make provisions for this. After the
conversion of the
format, the message N is supplied to the processor Pz in its processor-
specific format.
According to the above exemplary embodiment, it was assumed that the
conversion of the
data formats takes place in the processor P,. However, this is not a
limitation of the
invention. The conversion can also take place in the processor Pz. Moreover,
it can be
defined that the conversion is to be carried out exclusively during the
transmission of a
message N, or exclusively during the reception.

Representative Drawing