EP0354579A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A controller with a cache memory and control method of the cache memory
Assignee: Hitachi Microcomputer System Ltd
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Filing: 1989-08-10
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Granted: —
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Expires: 2009-08-10
Abstract
Abstract In a control unit having a cache memory (36), a method for selecting a loading method of data stored in the cache memory into the cache memory in accordance with an access pattern to the data, and an apparatus therefor are disclosed. The selection of the loading method is selection of control mode or procedure in accordance with the loading method, and it is attained by a learn function.
Inventors
- 👤 Akira Yamamoto
- 👤 Toshiaki Tsuboi
- 👤 Shigeo Honma
- 👤 Hiroyuki Kitajima
- 👤 Akira Kurano
- 👤 Masafumi Nozawa
- 👤 Katsunori Nakamura
- 👤 Kosaku Kambayashi
- 👤 Toshio Hitachi Sakawa Apartment 507 Nakano
- 👤 Yoshiro Shiroyanagi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 01:42
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/08; G06F12/0802; G06F12/0866; G06F12/0862; G06F2212/00; G06F2212/60; G06F2212/6026
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
76 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory, comprising the steps of: preparing a plurality of cache control modes; dividing a memory area of a memory device connected to the control unit into a plurality of memory areas; and switching from one to other of the cache control modes in accordance with operation status of each of said cache control modes regarding the respective divided memory areas.
Claim 2
Independent Claim
76 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory, comprising the steps of: preparing a plurality of cache control modes; dividing a memory area of a memory device connected to the control unit into a plurality of memory areas; and switching from one to other of the cache control modes in accordance with operation status of each of said cache control modes regarding the respective divided memory areas.
Claim 3
Dependent Claim
98 words
A method for controlling a cache memory according to Claim 1 further comprising the steps of: counting a number of times of accesses in the respective divided memory areas from a processing unit connected to said control unit; counting a number of times of valid and/or invalid operation of the currently selected one of the cache control modes in the respective divided memory areas, and obtaining said operation status based on the number of times of access and the number of times of valid and/or invalid operation of the cache control modes in the respective divided memory areas.
Claim 4
Dependent Claim
60 words
A method for controlling a cache memory according to Claim 1 wherein the cache control modes include a first mode for loading into the cache memory the data accessed by a processing unit connected to the control unit and stored in a memory device connected to the control unit and data stored in said memory device adjacently to said data.
Claim 5
Dependent Claim
91 words
A method for controlling a cache memory according to Claim 3 further comprising the steps of: counting a first number of times of access from the processing unit connected to the control unit; counting a second number of the cases where no access was made to the loaded data in the cache memory said loading; calculating a ratio of the first number of times to the second number of times; and switching from the first mode to other mode of the cache control modes when the ratio exceeds a predetermined value.
Claim 6
Dependent Claim
48 words
A method for controlling a cache memory according to Claim 1 wherein said control modes include a second mode for loading into the cache memory the data accessed from a processing unit connected to the control unit and stored in a memory device connected to the control unit.
Claim 7
Dependent Claim
102 words
A method for controlling a cache memory according to Claim 5 further comprising the steps of: counting a third number of times of accesses from the processing unit connected to the control unit; counting a fourth number of times of access to data stored in the memory device connected to the control unit adjacently to the data loaded into the cache memory by the second mode; calculating a ratio of the third number of times to the fourth number of times; and switching from the second mode to other mode of the cache control modes when the ratio exceeds a predetermined value.
Claim 8
Dependent Claim
115 words
A data processing system comprising: a processor (1); at least one memory device (2); and a control unit (31) connected to said processor and said memory device; said control unit including; a cache memory (36); control means having a plurality of cache control modes for controlling said cache memory to access from said processor to data stored in said memory device; dividing means for dividing a memory area of a memory device connected to the control unit into a plurality of memory areas; and switching means for switching from one to other of the cache control modes in accordance with operation status of each of the cache control modes regarding the respective divided memory area.
Claim 9
Dependent Claim
115 words
A data processing system comprising: a processor (1); at least one memory device (2); and a control unit (31) connected to said processor and said memory device; said control unit including; a cache memory (36); control means having a plurality of cache control modes for controlling said cache memory to access from said processor to data stored in said memory device; dividing means for dividing a memory area of a memory device connected to the control unit into a plurality of memory areas; and switching means for switching from one to other of the cache control modes in accordance with operation status of each of the cache control modes regarding the respective divided memory area.
Claim 10
Independent Claim
132 words
A method for controlling a cache memory (36) by a control unit (31) having said cache memory comprising the steps of; fetching first data from a memory device which is connected to said control unit and comprises a plurality of physical areas when first data to be accessed is not in said cache memory from a processing unit connected to said control unit; loading said first data into said cache memory; fetching from said memory device, second data which is data excluding said first data from all the data which is stored in said physical area which includes said first data when third data to be accessed from said processing unit is included in said physical area which includes said first data; and loading the said second data into said cache memory.
Claim 11
Independent Claim
132 words
A method for controlling a cache memory (36) by a control unit (31) having said cache memory comprising the steps of; fetching first data from a memory device which is connected to said control unit and comprises a plurality of physical areas when first data to be accessed is not in said cache memory from a processing unit connected to said control unit; loading said first data into said cache memory; fetching from said memory device, second data which is data excluding said first data from all the data which is stored in said physical area which includes said first data when third data to be accessed from said processing unit is included in said physical area which includes said first data; and loading the said second data into said cache memory.
Claim 12
Dependent Claim
77 words
A method for controlling a cache memory according claim 8 wherein step of fetching said third data includes the steps of; fetching the data from the position which is located immediately behind said first data, to the end of the said physical area which includes said first data; and fetching the data from the head of the said physical area which includes said first data, to the position which is located immediately ahead of said first data.
Claim 13
Independent Claim
148 words
A method for controlling a cache memory (36) by a control unit (31) having a cache memory comprising the steps of; fetching a first data from a memory device which is connected to said control unit and comprises a plurality of physical area when first data to be accessed is not in said cache memory from a processing unit connected to said control unit; loading said first data into said cache memory; fetching from the said memory device, second data which is stored in the range from the head of said physical area which includes said first data, to the position which is located immediately ahead of said first data when third data to be accessed from said processing unit is located ahead of said first data and is included in said physical area which includes said first data; and loading said second data into said cache memory.
Claim 14
Independent Claim
148 words
A method for controlling a cache memory (36) by a control unit (31) having a cache memory comprising the steps of; fetching a first data from a memory device which is connected to said control unit and comprises a plurality of physical area when first data to be accessed is not in said cache memory from a processing unit connected to said control unit; loading said first data into said cache memory; fetching from the said memory device, second data which is stored in the range from the head of said physical area which includes said first data, to the position which is located immediately ahead of said first data when third data to be accessed from said processing unit is located ahead of said first data and is included in said physical area which includes said first data; and loading said second data into said cache memory.
Claim 15
Independent Claim
145 words
A method for controlling a cache memory (36) by a control unit (31) having a cache memory comprising the steps of; fetching a first data from a memory device which is connected to said control unit and comprises a plurality of physical areas when first data to be accessed is not in said cache memory from a processing unit connected to said control unit; loading said first data into said cache memory; fetching from said memory device, second data which is stored in the range from the position which is located immediately behind said first data, to the end of said physical area which includes said first data when third data to be accessed from said processing unit is located behind said first data and is included in said physical area which includes said first data; and loading said second data into said cache memory.
Claim 16
Independent Claim
145 words
A method for controlling a cache memory (36) by a control unit (31) having a cache memory comprising the steps of; fetching a first data from a memory device which is connected to said control unit and comprises a plurality of physical areas when first data to be accessed is not in said cache memory from a processing unit connected to said control unit; loading said first data into said cache memory; fetching from said memory device, second data which is stored in the range from the position which is located immediately behind said first data, to the end of said physical area which includes said first data when third data to be accessed from said processing unit is located behind said first data and is included in said physical area which includes said first data; and loading said second data into said cache memory.
Claim 17
Independent Claim
140 words
A method for controlling a cache memory (36) by a control unit (31) having a cache memory comprising the steps of; fetching said first data from a memory device which is connected to said control unit and comprises a plurality of physical areas when first data to be accessed is not in said cache memory from a processing unit, connected to said control unit; loading said first data into said cache memory; fetching from said memory device, second data which is data excluding the first data from all the data which is stored in said physical area which includes said first data when third data to be accessed from said processing unit is located ahead of said first data and is included in said physical area which includes said first data; and loading said second data into said cache memory.
Claim 18
Independent Claim
140 words
A method for controlling a cache memory (36) by a control unit (31) having a cache memory comprising the steps of; fetching said first data from a memory device which is connected to said control unit and comprises a plurality of physical areas when first data to be accessed is not in said cache memory from a processing unit, connected to said control unit; loading said first data into said cache memory; fetching from said memory device, second data which is data excluding the first data from all the data which is stored in said physical area which includes said first data when third data to be accessed from said processing unit is located ahead of said first data and is included in said physical area which includes said first data; and loading said second data into said cache memory.
Claim 19
Independent Claim
160 words
A method for controlling a cache memory (36) by a control unit (31) having a cache memory comprising the steps of; receiving an access request which includes a designation of the data to be accessed and an additional loading instruction from a processing unit connected to said control unit; fetching said first data from a memory device which is connected to said control unit and comprises a plurality of physical areas when first data to be accessed is not in said cache memory from a processing unit connected to said control unit; loading said first data into said cache memory; fetching from said memory device, second data which is data excluding the first data from all the data which is stored in said physical area which includes said first data when third data to be accessed from said processing unit is included in said physical area which includes said first data; and loading said second data into said cache memory.
Claim 20
Independent Claim
160 words
A method for controlling a cache memory (36) by a control unit (31) having a cache memory comprising the steps of; receiving an access request which includes a designation of the data to be accessed and an additional loading instruction from a processing unit connected to said control unit; fetching said first data from a memory device which is connected to said control unit and comprises a plurality of physical areas when first data to be accessed is not in said cache memory from a processing unit connected to said control unit; loading said first data into said cache memory; fetching from said memory device, second data which is data excluding the first data from all the data which is stored in said physical area which includes said first data when third data to be accessed from said processing unit is included in said physical area which includes said first data; and loading said second data into said cache memory.
Claim 21
Independent Claim
106 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory having a memory area thereof divided into a plurality of segments, comprising the steps of: obtaining at least one of the segments having a size equal to or larger than a size of first data to be accessed from a processing unit connected to the control unit when the data to be accessed is not in the cache memory; loading the first data to be accessed from a memory device connected to the control unit; and loading the first data to be accessed into said at least one segment.
Claim 22
Independent Claim
106 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory having a memory area thereof divided into a plurality of segments, comprising the steps of: obtaining at least one of the segments having a size equal to or larger than a size of first data to be accessed from a processing unit connected to the control unit when the data to be accessed is not in the cache memory; loading the first data to be accessed from a memory device connected to the control unit; and loading the first data to be accessed into said at least one segment.
Claim 23
Dependent Claim
75 words
A method for controlling a cache memory according to Claim 14 further comprising the steps of: obtaining at least one of the segments having a size equal to or larger than a size of second data to be accessed relating to the first data; loading the data related to the second data to be accessed relating to said first data from the memory device; and loading the loaded data into said at least one segment.
Claim 24
Independent Claim
91 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory having a predetermined size of memory area as a management unit, comprising the steps of: fetching data from a physical area of a memory device connected to the control unit; loading the data into one management unit of the cache memory; recognizing a pattern of access to the data in said management unit from a processing unit connected to the control unit; and reloading data from said physical area in accordance with the pattern.
Claim 25
Independent Claim
91 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory having a predetermined size of memory area as a management unit, comprising the steps of: fetching data from a physical area of a memory device connected to the control unit; loading the data into one management unit of the cache memory; recognizing a pattern of access to the data in said management unit from a processing unit connected to the control unit; and reloading data from said physical area in accordance with the pattern.
Claim 26
Independent Claim
101 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory, comprising the steps of: receiving an access request for data to be accessed from a processing unit connected to the control unit; executing first recognition process in which it is recognized that the access is a sequential access; fetching first data to be accessed and succeeding data to said first data from a memory unit connected to the control unit in accordance with the execution result of said first recognition process; and loading said first data and said succeeding data into the cache memory.
Claim 27
Independent Claim
101 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory, comprising the steps of: receiving an access request for data to be accessed from a processing unit connected to the control unit; executing first recognition process in which it is recognized that the access is a sequential access; fetching first data to be accessed and succeeding data to said first data from a memory unit connected to the control unit in accordance with the execution result of said first recognition process; and loading said first data and said succeeding data into the cache memory.
Claim 28
Dependent Claim
52 words
A method for controlling a cache memory according to Claim 17 further comprising the steps of: executing second recognition process in which it is recognized that said access request is not a sequential access; and fetching data from the memory device in accordance with the execution result of said second recognition process.
Claim 29
Independent Claim
106 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory, comprising the steps of: receiving an access request for data from a processing unit connected to the control unit; executing recognition process in which it is recognized that the data stored ahead of the data to be accessed and stored in a memory device connected to the control unit has been substantially sequentially accessed; fetching the data to be accessed and succeeding data from the memory device in accordance with the execution result of said recognition process; and loading said data and said succeeding data into the cache memory.
Claim 30
Independent Claim
106 words
A method for controlling a cache memory (36) by a control unit (31) having the cache memory, comprising the steps of: receiving an access request for data from a processing unit connected to the control unit; executing recognition process in which it is recognized that the data stored ahead of the data to be accessed and stored in a memory device connected to the control unit has been substantially sequentially accessed; fetching the data to be accessed and succeeding data from the memory device in accordance with the execution result of said recognition process; and loading said data and said succeeding data into the cache memory.
Claim 31
Dependent Claim
93 words
A control unit comprising: a cache memory (36); first input means for inputting an access request for data; retrieve means for seaching the cache memory in response to the data access request issued by said first input means; second input means for fetching data required by said access request and related data from a memory device connected to the control unit when said retrieve means cannot retrieve the data by the access request; and load means for loading the data requested by the access request and the related data into said cache memory.
Claim 32
Dependent Claim
93 words
A control unit comprising: a cache memory (36); first input means for inputting an access request for data; retrieve means for seaching the cache memory in response to the data access request issued by said first input means; second input means for fetching data required by said access request and related data from a memory device connected to the control unit when said retrieve means cannot retrieve the data by the access request; and load means for loading the data requested by the access request and the related data into said cache memory.
Claim 33
Dependent Claim
53 words
A control unit according to Claim 20 wherein said cache memory is divided into management units of a predetermined memory size, and said second input means fetches the data to be loaded in the same management unit of the cache memory as the data required by the access request, as the related data.
Claim 34
Dependent Claim
95 words
A control unit comprising: a cache memory (36); first input means for inputting an access request for data; recognition means for recognizing that the access request issued by said first input means is a sequential access request; second input means for fetching data required by the access request and succeeding data from a memory device connected to the control unit in accordance with the recognition by said recognition means; and load means for loading the data required by the access request and the succeeding data fetched by said second input means into said cache memory.
Claim 35
Dependent Claim
95 words
A control unit comprising: a cache memory (36); first input means for inputting an access request for data; recognition means for recognizing that the access request issued by said first input means is a sequential access request; second input means for fetching data required by the access request and succeeding data from a memory device connected to the control unit in accordance with the recognition by said recognition means; and load means for loading the data required by the access request and the succeeding data fetched by said second input means into said cache memory.
Claim 36
Independent Claim
53 words
A method for controlling a cache memory having a memory area of a predetermined size as a management unit, comprising the steps of: recognizing an access pattern to data loaded in one of said management units in the cache memory; and restoring said data into the cache memory by referencing the access pattern.
Claim 37
Independent Claim
53 words
A method for controlling a cache memory having a memory area of a predetermined size as a management unit, comprising the steps of: recognizing an access pattern to data loaded in one of said management units in the cache memory; and restoring said data into the cache memory by referencing the access pattern.
References Cited (Backward Citations)
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