Communication control system and information processing system

Information of a plurality of operation modes is stored in memory. Information of temporary protocols and true protocols is associated with event numbers and processing state numbers, then stored in a status transition table circuit. When an event number and a processing state number are set in an input register, a CPU selects a temporary protocol according to the event number and processing state number. Then, the CPU retrieves an operation mode associated with the temporary protocol from memory, selects a true protocol according to the retrieved operation mode, then executes information processing according to the true protocol.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a communication control system and an 
information processing system, or more particularly, to a communication 
control system and information processing system based on table retrieval 
for retrieving a status transition table specifying protocols and 
information processing procedures. 
2. Description of the Related Art 
In a communication control system, complex status transition has been 
executed to follow a protocol based on a recommendation standardized as an 
international standard in the past. A popular method of executing status 
transition at a high speed has been described, for example, in Japanese 
Patent Laid-Open No. 64-65653. The protocol is proceeded as follows: 
(a) frames are received from a remote station, 
(b) the frames are classified, and event numbers are created according to 
the contents, 
(c) status transition is executed according to an event number and a 
current state number, then a processing number to be executed next and a 
next state number to which control passes are retrieved, then 
(d) processing is executed according to a protocol associated with the 
calculated processing number. 
In the above protocol, status transition is carried out as described below. 
That is to say, when a status transition table is retrieved, an address 
made up of an event number and a current state number (accessed at the 
start of table retrieval) is used to access the status transition table. 
Then, a next state number and processing number specified by this access 
are extracted from the status transition table. The next state number is 
used as a current state number for the next status transition. The 
processing number is used as an address of a corresponding processing 
program. By executing this process, a specific processing number and next 
state number are extracted from the status transition table according to 
an event number and a current state number. 
However, according to the foregoing prior art, when an event number and a 
current state number are used as a set of input information, the set of 
input information yields only one processing number. Therefore, a set of 
input information cannot enable communication in association with multiple 
operation modes. This means that when a specific processing number is 
extracted according to an event number and a current state number, only 
one processing number is selected despite differences of operation modes. 
SUMMARY OF THE INVENTION 
The object of the present invention is to provide a communication control 
system and an information processing system capable of executing 
processing in association with multiple operation modes, and to provide a 
microcomputer including the communication control system or information 
processing system. 
To achieve the foregoing object, the present invention provides a 
communication control system as a first system that comprises an event 
number setting means for setting an event number fetched from input 
communication information, a processing state number setting means for 
setting a designated processing state number every time an event number is 
set, a sub-protocol storage means for storing information of temporary 
protocols associated with event numbers and processing state numbers, an 
operation mode setting means for setting multiple operation modes in 
association with the temporary protocols, a sub-protocol selecting means 
for retrieving information of a designated protocol from the sub-protocol 
storage means according to an event number the set by event number setting 
means and a processing set by state number the processing state number 
setting means and, an operation mode selecting means for selecting a 
designated operation mode according to temporary protocol information 
provided by the sub-protocol selecting means. The communication control 
system of the first system further comprises main protocol storage means 
for storing information of true protocols associated with operation modes, 
a main protocol selecting means for retrieving information of a true 
protocol from the main protocol storage means according to an operation 
mode selected by the operation mode selecting means, an information 
processing means for executing information processing according to a true 
protocol provided by the main protocol selecting means, and a processing 
state number designating means for designating a next processing state 
number for the processing state number setting means with running of the 
information processing means. 
The second system is a communication control system comprising an event 
number setting means for setting an event number fetched from input 
communication information, a processing state number setting means for 
setting a designated processing state number every time an event number is 
set, an operation mode storage means for storing multiple operation modes 
in association with event numbers and processing state numbers, an 
operation mode selecting means for retrieving a designated operation mode 
from the designated event number setting means according to an event 
number set by the event number setting means and a processing state number 
set by the processing state number setting means, an auxiliary event 
number creating means for creating an auxiliary event number associated 
with an operation mode according to an event number set by the event 
number setting means and, an auxiliary processing state number creating 
means for creating an auxiliary processing state number associated with an 
operation mode according to a processing state number set by the 
processing state number setting means control system of the second system 
further comprises a protocol storage means for storing information of true 
protocols associated with auxiliary event numbers and auxiliary processing 
state numbers, a protocol selecting means for retrieving information of a 
true protocol from the protocol storage means according to a created 
auxiliary event number and auxiliary processing state number, an 
information processing means for executing information processing 
according to a true protocol provided by the protocol selecting means, and 
a processing state number designating means for designating a next 
processing state number for the processing state number setting means with 
running of the information processing means. 
The third system is a communication control system comprising an event 
number setting means for setting an event number fetched from input 
communication information, a processing state number setting means for 
setting a designated processing state number every time an event number is 
set, an operation mode setting means for setting a designated operation 
mode every time an event number is set, an event number checking means for 
determining whether an event number set by the event number setting means 
falls within a setting range, an auxiliary event number creating means for 
creating an auxiliary event number associated with an operation mode set 
by the operation mode setting means according to an event number when the 
event number checking means determines that the event number set by the 
event number setting means falls within a setting range, a processing 
state number checking means for determining whether a processing state 
number set by the processing state number setting means falls within a 
setting range, and an auxiliary processing state number creating means for 
creating an auxiliary processing state number associated with an operation 
mode set by the operation mode setting means according to a processing 
state number when the processing state number checking means determines 
that the processing number set by the processing state number setting 
means falls within a setting range. The communication control system of 
the third system further comprises a protocol storage means for storing 
information of multiple protocols associated with auxiliary event numbers 
and auxiliary processing state numbers, a protocol selecting means for 
retrieving information of a designated protocol from the protocol storage 
means according to an auxiliary event number created by the auxiliary 
event number creating means and an auxiliary processing state number 
created by the auxiliary processing number creating means, an information 
processing means for executing information processing according to a 
protocol provided by the processing protocol selecting means, and a 
processing state number designating means for designating a next 
processing state number for the processing state number setting means with 
running of the information processing means. 
The fourth system is a communication control system comprising an event 
number setting means for setting an event number fetched from input 
communication information, a processing state number setting means for 
setting a designated processing state number every time an event number is 
set, a protocol storage means for storing information of multiple 
protocols associated with event numbers and processing numbers, a protocol 
selecting means for retrieving information of a designated protocol from 
the protocol storage means according to an event number set by the event 
number setting means and a processing state number set by the processing 
state number setting means, an operation mode storage means for storing 
operation modes in association with protocols, an operation mode selecting 
means for retrieving a designated operation mode from the operation mode 
storage means according to a protocol provided by the protocol selecting 
means and, a processing module storage means for storing operation modules 
in association with operation modes. The communication control system of 
the fourth system further comprises a processing module selecting means 
for retrieving a designated processing module from the processing module 
storage means according to an operation mode provided by the operation 
mode selecting means, a processing module executing means for executing a 
processing module selected by the processing module selecting means, and a 
processing state number designating means for designating a next 
processing state number for the processing state number setting means with 
execution of a processing module. 
The fifth system is an information processing system comprising an event 
type setting means for setting an event type fetched from input 
information, an information processing state setting means for setting a 
designated information processing state every time an event type is set, a 
sub-processing procedure storage means for storing information of 
temporary information processing procedures associated with event types 
and processing states, an operation mode setting means for setting 
multiple operation modes in association with temporary information 
processing procedures, and a sub-processing procedure selecting means for 
retrieving information of a designated information processing procedure 
from the sub-processing procedure storage means according to an event type 
set by the event type setting means and an information processing state 
set by the information processing state setting means sets. The 
information processing system of the fifth system further comprises an 
operation mode selecting means for selecting a designated operation mode 
according to a temporary information processing procedure provided by the 
sub-processing procedure selecting means, a main processing procedure 
storage means for storing information of true information processing 
procedures in association with operation modes, a main processing 
procedure selecting means for retrieving information of a true information 
processing procedure from the main processing procedure storage means 
according to an operation mode provided by the operation mode selecting 
means, an information processing means for executing information 
processing according to a true information processing procedure provided 
by the main processing procedure selecting means, an information 
processing state designating means for designating a next information 
processing state for the information processing state setting means with 
running of the information processing means. 
The sixth system is an information processing system comprising an event 
type setting means for setting an event type fetched from input 
information, an information processing state setting means for setting a 
designated information processing state every time an event type is set, 
an operation mode storage means for storing multiple operation modes in 
association with event types and information processing states, an 
operation mode selecting means for retrieving a designated operation mode 
from the operation mode storage means according to an event type set by 
the event setting means and an information processing state set by the 
information processing state setting means, an auxiliary event type 
creating means for creating an auxiliary event type associated with an 
operation mode according to an event type set by the event type setting 
means, an auxiliary information processing state creating means for 
creating an auxiliary information processing state associated with an 
operation mode according to an information processing state set by the 
information processing state setting means, a processing procedure storage 
means for storing true processing procedures in association with event 
types and auxiliary information states. The information processing system 
of the sixth system further comprises a processing procedure selecting 
means for retrieving information of a true information processing 
procedure from the information processing procedure storage means 
according to a created auxiliary event type and auxiliary information 
processing state, an information processing means for executing 
information processing according to a true information processing 
procedure provided by the processing procedure selecting means, and an 
information processing state designating means for designating a next 
information processing state for the information processing state setting 
means with running of the information processing means. 
The seventh system is an information processing system comprising an event 
type setting means for setting an event type fetched from input 
information, an information processing state setting means for setting a 
designated information processing state every time an event type is set, 
an operation mode setting means for setting a designated operation mode 
every time an event type is set, an event type checking means for 
determining whether an event type set by the event type setting means 
falls within a setting range, an auxiliary event type creating means for 
creating an auxiliary event type associated with an operation mode set by 
the operation mode setting means according to an event type when the event 
type checking means determines that the event type set by the event type 
setting means falls within a setting range, an information processing 
state checking means for determining whether an information processing 
state set by the information processing state setting means falls within a 
setting range, an auxiliary information processing state creating means 
for creating an auxiliary information processing state associated with an 
operation mode set by the operation mode setting means according to an 
information processing state when the information processing state 
checking means determines that the information processing state set by the 
information state setting means falls within a setting range, and a 
processing procedure storage means for storing information of multiple 
information processing procedures associated with auxiliary event types 
and auxiliary information processing states. The information processing 
system of the seventh system further comprises a processing procedure 
selecting means for retrieving information of a designated information 
processing procedure from the processing procedure storage means according 
to an auxiliary event type created by the auxiliary event type creating 
means and an auxiliary information processing state created by the 
auxiliary information processing state creating means creates, an 
information processing means for executing information processing 
according to an information processing procedure provided by the 
information processing procedure selecting means, and an information 
processing state designating means for designating a next information 
processing sate for the information processing state setting means with 
with running of the information processing means. 
The eighth system is an information processing system comprising an event 
type setting means for setting an event type fetched from input 
information, an information processing state setting means for setting a 
designated information processing state every time an event type is set, a 
processing procedure storage means for storing information of multiple 
information processing procedures associated with event types and 
information processing states, a processing procedure selecting means for 
retrieving information of a designated information processing procedure 
from the processing procedure storage means according to an event type set 
by the event type setting means and an information processing state set by 
the information processing state setting means, an operation mode storage 
means for storing operation modes in association with information 
processing procedures and, an operation mode selecting means for 
retrieving a designated operation mode from the operation mode storage 
means according to an information processing procedure provided by the 
information processing procedure selecting means. The information 
processing system of the eighth system further comprises a processing 
module storage means for storing processing modules in association with 
operation modes, a processing module selecting means for retrieving a 
designated processing module from the processing module storage means 
according to an operation mode provided by the operation mode selecting 
means, a processing module executing means for executing a processing 
module provided by the processing module selecting means provides, and an 
information processing state designating means for designating a next 
information processing state for the information processing state setting 
means with execution of a processing module. 
The ninth system is a microcomputer having any of the first to eighth 
systems as a main component. 
In the first embodiment of the invention, first, a temporary protocol is 
extracted according to an event number and a current state number. Then, 
an operation mode is selected in association with the temporary protocol, 
and a true protocol is selected according to the operation mode. Next, 
information processing is executed according to the true protocol. With 
the execution, a next processing state number is designated. Thus, when a 
temporary protocol is extracted, a specific protocol can be selected from 
true protocols according to an operation mode. 
The second embodiment of the invention selects a specific operation mode 
according to an event number and a current state number. Then, a protocol 
associated with the operation mode is extracted from true protocols. 
Information processing is executed according to the extracted protocol. 
With the execution, a next processing state number is designated. More 
specifically, a designated operation mode is selected from operation modes 
according to the event number and current state number. Then, a protocol 
is selected in association with the selected operation mode. Thus, when an 
event number and a current state number are set to specify an operation 
mode, a protocol associated with the operation mode can be extracted from 
multiple protocols. 
The third embodiment of the invention sets multiple protocols in 
association with auxiliary event numbers and auxiliary processing state 
numbers. Then, when an event number and a current state number fall within 
the setting ranges, an auxiliary event number and an auxiliary state 
processing number are created according to an operation mode. A protocol 
associated with the auxiliary event number and auxiliary state number is 
extracted from multiple protocols. Then, information processing is 
executed according to the extracted protocol. With the execution, a next 
processing state number is designated. More specifically, when an event 
number and a processing slate number falling within the setting ranges are 
set, the numbers are converted into an auxiliary event number and an 
auxiliary processing state number. Thus, an operation mode is selected 
from operation modes according to the auxiliary event number and auxiliary 
processing state number. Eventually, communication is executed according 
to the operation mode. 
In the fourth embodiment of the invention, a designated protocol is 
selected according to an event number and a processing state number, then 
an operation mode is selected from operation modes according to the 
selected protocol. Then, a processing module associated with the operation 
mode is extracted from processing modules. Then, the extracted processing 
module is executed. With the execution, a next processing state number is 
designated. Specifically, multiple processing modules are set in 
accordance with operation modes, and a processing module associated with 
any of the operation modes is executed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The embodiment of the present invention will be described in conjunction 
with the drawings. 
In FIG. 2, a communication control system 10 is formed with a 
microcomputer, which is connected to another station over a communication 
line 12 and to a host processor 16 and an external memory 18 over a system 
bus 14. The communication control system 10 comprises an input register 
20, a status transition table circuit 22, an output register 24, a CPU 26, 
a microprogram ROM 28, an internal bus 30, a circuit control 32, a memory 
34, and a system interface control 36. The circuit control 32 is connected 
to the communication line 12, and the system interface control 36 is 
connected to the system bus 14. 
Various communication information is supplied to the circuit control 32 
over the communication line 12. Event numbers of frames included in input 
communication information are set in the input resistor 20. An operation 
mode is set in response to an instruction from the host processor 16. 
Then, various operation modes are stored in the memory 34. The status 
transition table circuit 22 includes, as shown in FIG. 3, memory areas 
associated with current state numbers 0 to 31 and event numbers 0 to 127 
that are accessed at the start of table retrieval. The memory areas 
contain processing numbers representing protocols, and next state numbers 
or numbers to be accessed next. A processing number 200 associated with a 
temporary protocol and a next state number 10 are stored in a specific 
area of the memory areas, or a memory area associated with a current state 
number 10 and an event number 20. Then, when the status transition table 
circuit 22 is accessed in response to an instruction from the CPU 26, a 
processing number and next state number fetched from a designated memory 
area are set in the output resister 24. Programs for executing these 
operations are stored in the microprogram ROM 28. 
In the first embodiment of the invention executing protocol selection using 
software, as shown in FIGS. 1 and 4, when an event number 20 is fetched 
from input communication information and 10 is set as a current state 
number in an input resister 20, a status transition table is retrieved 
according to these numbers. Based on the current state number 10 and event 
number 20, a processing number 200 representing a temporary protocol and a 
next state number 10 are extracted. When the processing number 200 is 
extracted, an operation mode placed in memory 34 is checked at a step 100. 
In the first embodiment of the invention, it is determined whether the 
operation mode is .varies., .beta., or .gamma.. Then, if the operation 
mode is determined to be .varies., 100 is specified as a processing number 
representing a true protocol, and 10, as a next state number at a step 
102. When the operation mode is determined to be .beta., the next state 
number is changed to 12 at a step 104. Then, the processing number 
associated with the true protocol is changed to 110 at a step 106. When 
the operation mode is determined to be .gamma., the next state number is 
changed to 15 at a step 108. Then, a processing number 120 is selected at 
a step 110. 
When a processing number 100 is selected as a true protocol, information 
processing associated with the processing number 100 is executed. When a 
processing number 110 or 120 is selected, information processing 
associated with the processing number is executed. When the processing 
number 100 is selected, 10 is set as the next state number in the input 
resister 20. When the processing number 110 is selected, 12 is set as the 
next state number. When the processing number 120 is selected, 15 is set 
as the next state number. 
Thus, according to the first embodiment of the invention, when a processing 
number 200 is selected according to a current state number 10 and an event 
number 20, three kinds of processing numbers are selected in association 
with operation modes. Therefore, a single communication control system 10 
can execute information processing based on multiple protocols in 
association with operation modes. 
In the foregoing embodiment, other memory areas except a memory area 
containing a processing number 200 that is specified with a current state 
number 10 and an event number 20 have processing numbers associated with 
true protocols. When any of these processing numbers is selected, 
processing is executed according to the selected processing number 
irrelative to an operation mode. 
When hardware is employed to carry out the processing of the aforesaid 
embodiment, a configuration shown in FIGS. 5 and 6 is adopted. 
A current state number register 38 and an event number register 40 
correspond to an input register 20. A ROM 42 serves as a memory 
corresponding to a status transition table circuit 22. A next state number 
register 44 and a processing number register 48 correspond to an output 
register 24. A processing number adder 46, a processing number comparator 
50, and an operation mode register 52 are installed to set processing 
numbers in the processing number register 48. The memory areas of the ROM 
42 contain data of processing numbers in association with table addresses. 
The table addresses 0 to 207 contain processing numbers 0 to 207 in 
association with true protocols. The table addresses 208 to 255 contain 
processing numbers in association with temporary protocols. Of these table 
addresses, the table addresses 208 to 223 contain data of .varies.-mode 
processing numbers. The table addresses 224 to 239 contain data of 
.beta.-mode processing numbers. The table addresses 240 to 255 contain 
data of .gamma.-mode processing numbers. 
In the foregoing configuration, when a designated current state number and 
event number are set in the current state number register 38 and event 
number register 40, a processing number associated with the current state 
number and event number is fetched from the ROM 42. When the processing 
number is 207 or less, the processing number is set in the processing 
register 48 as it is. On the other hand, when the processing number 
comparator 50 determines that the processing number exceeds 208, a value 
associated with an operation mode is set in the processing number adder 
46. For example, when the operation mode set in the operation mode 
register 52 is an .varies. mode, 0 is added in. When the operation mode is 
a .beta. mode, +16 is added in. When the operation mode is a .gamma. mode. 
+32 is added in. To be more specific, when processing common among the 
operation modes is executed, a processing number ranging from 0 to 207 is 
selected. When processing different among the operation modes is executed, 
a processing number is selected according to an operation mode. Thereby, 
similarly to the aforesaid embodiment, a single communication control 
system 10 can execute information processing based on multiple protocols 
in association with operation modes. When a single LSI is used to form the 
communication control system 10, the system can be designed compactly at 
minimum manufacturing cost. Alternatively, hardware may be used. In this 
case, a variety of operations can be done simultaneously to realize 
high-speed processing. 
Next, the second embodiment of the invention will be described in 
conjunction with FIGS. 1 to 9. In this embodiment, when a current state 
number ranges from 10 to 12 and an event number ranges from 20 to 24, a 
combination of an event number and a current state number remains 
unchanged in .varies. mode. The combination is changed to 24 and 12 in 
.beta. mode, while the combination is changed to 25 to 29 and 13 to 15 in 
.gamma. mode. 
A status transition table circuit 22 in the second embodiment of the 
invention is configured to have memory areas shown in FIG. 9. When frame 
classification is carried out on receipt of input communication 
information, an event number is created according to the frame at a step 
200. Then, operation mode classification is performed at a step 202. 
During the operation mode classification, it is determined whether or not 
to change the event number and a current state number at a step 204. That 
is to say, it is determined whether any value of 10 to 12 is set as a 
current state number and any value of 20 to 24 is set as an event number. 
If the result of the determination is negative, the status transition 
table is retrieved as it is. If the result of the determination is 
affirmative, the operation mode is checked at a step 206. When the 
operation mode is determined to be .varies., the current state number 
ranging from 10 to 12 and the event number ranging from 20 to 24 remains 
unchanged, then table retrieval is executed to retrieve a processing 
number and a next state number From an area specified with the current 
state number and event number at a step 216. 
On the other hand, if the operation mode is determined to be .beta., the 
event number is changed to 24 forcibly at a step 208. The current state 
number is changed to 12 forcibly at a step 210. Then, at a step 216, a 
processing number and a next state number are extracted From a memory area 
associated with the current state number 12 and event number 24. Then, 
information processing is executed according to the processing number. If 
the operation mode is determined to be .gamma., +5 is added to the event 
number to create an auxiliary event number at a step 212. Then, +3 is 
added to the current state number to create an auxiliary current state 
number at a step 210. That is to say, when an event number ranging from 20 
to 24 and a current state number ranging from 10 to 12 are designated, the 
event number is changed to range 25 to 29 and the current state number is 
changed to range 13 to 15. Then, a processing number and a next state 
number are retrieved from a memory area associated with the auxiliary 
event number and auxiliary current state number. Then, information 
processing is executed according to the retrieved processing number. Thus, 
the second embodiment of the invention also enables execution of status 
transition according to an operation mode. 
Next, the third embodiment of the invention will be described in 
conjunction with FIGS. 10 to 12. 
In the third embodiment of the invention or a variant of the embodiment of 
the invention, hardware is used to execute various operations. Various 
registers and processing circuits include a current state number register 
54, a current state number comparator 56, a current state number adder 58, 
an event number register 60, an event number adder 62, an event number 
comparator 64, an operation mode register 66, a ROM 68, a next state 
number register 70, and a processing number register 72. The ROM 68 
contain, as shown in FIG. 12, information of protocols associated with 
event numbers and current state numbers and information of protocols 
associated with auxiliary event numbers and auxiliary current stent 
numbers. 
In the foregoing configuration, when a number ranging from 0 to 19 is set 
in the current state number register 54 and a number ranging from 0 to 79 
is set in the event number register, these numbers pass through the 
current state number adder 58 and event number adder 62 respectively. 
Then, table retrieval is performed according to the event number and 
current state number. Specifically, a state processing number common among 
modes is extracted. Then, information processing is performed according to 
the extracted processing number. 
On the other hand, when the current state number comparator 56 determines 
that the specified current state number exceeds 79, and the event number 
comparator 64 determines that the specified event number exceeds 79, 
values associated with an operation mode the operation mode register 66 
specifies are added to the current state number and event number. For 
example, when the operation mode is an .varies. mode, 0 is added to a 
current state number and an event number. That is to say, in the .varies. 
mode, any event number ranging from 80 to 95 and any current state number 
ranging from 20 to 23 are set as they are. On the other hand, when the 
operation mode is a .beta. mode, +16 is added to an event number and +4 is 
added to a current state number. Thus, an auxiliary event number and an 
auxiliary current state number are created. In the .beta. mode, an event 
number ranging from 80 to 95 is converted to an auxiliary event number 
ranging from 96 to 111. A current state number ranging from 20 to 23 is 
converted to an auxiliary current state number ranging from 24 to 27. When 
the operation mode is .gamma., +32 is added to an event number, and +8, to 
a current state number. An event number ranging from 80 to 95 is converted 
to an auxiliary event number ranging from 112 to 127, and a current state 
number ranging from 20 to 23, to an auxiliary current State number ranging 
from 28 to 31. When the .beta. mode or .gamma. mode is specified, data of 
a processing number and a next state number is extracted from a memory 
area associated with the auxiliary event number and auxiliary current 
state number. The data values are set in the processing number register 72 
and in the next state number register 70. 
As mentioned above, according to the present embodiment, when an event 
number and a current state number fall within setting ranges, a specific 
processing number and next state number are retrieved from a status 
transition table according to an operation mode. Thus, communication can 
be executed in association with multiple operation modes. 
Next, the fourth embodiment of the invention will be described in 
conjunction with FIGS. 13 and 14. 
The fourth embodiment of the invention is implemented in software. After 
communication information is received to fetch frames at a step 300, frame 
classification is performed to create event numbers for the frames at a 
step 302. Then, a status transition table is retrieved according to an 
event number and a current state number at a step 304. This retrieval 
specifies protocol selection at a step 306. Then, processing shown in FIG. 
14 is executed. First, operations A and B of a subroutine are executed at 
steps 400 and 402. Then, an operation mode is checked at a step 404. When 
the checking determines that the operation mode is an .varies. mode, 
.varies.-mode processing modules or programs C11 and C12 are executed at 
steps 406 and 408. When the operation mode is a mode, a processing module 
or a program C21 is executed at a step 410. On the other hand, when the 
operation mode is .beta., processing modules or programs C31, C32, and C33 
are executed at steps 412, 414, and 416. After that, a processing module 
or a program D is executed at step 418. Thus, protocol selection is formed 
with multiple processing modules. When a combination of processing modules 
differs among operation modes, an operation mode is determined first, then 
processing modules associated with the operation mode are executed. In 
other words, an operation mode is classified not to specify a processing 
number but to specify processing modules for protocol selection. Then, 
processing is executed according to the classified operation mode. 
Thereby, processing modules can be executed in association with multiple 
operation modes. 
The aforesaid embodiments have been described in relation to a 
communication control system. The embodiments can also apply to an 
information processing system in which information processing procedures 
are associated with event types and information processing states and 
information processing is executed according to any of the information 
processing procedures. 
As described above, according to the present invention, various kinds of 
information processing can be executed in association with multiple 
operation modes. Multiple kinds of information processing can be executed 
under a single communication control system or information processing 
system. Therefore, a system can be designed compactly at low manufacturing 
cost.