ACCESS KEY GENERATING APPARATUS AND INFORMATION PROCESSING APPARATUS
First Claim
1. An access key generating apparatus comprising:
- a bit field converting unit which converts a partial bit field, as a portion of a bit field indicating a device identifier of peripheral devices, into a reduced bit field having a bit width shorter than a bit width of the partial bit field;
an access key retaining unit which retains a plurality of access keys to control access to a memory from the peripheral devices in association with each of the peripheral devices; and
an indexing unit which indexes the access keys from the access key retaining unit using an index address including the reduced bit field if the conversion of the partial bit field into the reduced bit field is successful, and indexes the access keys from the access key retaining unit using an index address including the partial bit field if the conversion of the partial bit field into the reduced bit field is unsuccessful.
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Accused Products
Abstract
An access key generating apparatus includes: a bit field converting unit which converts a partial bit field into a reduced bit field having a bit width shorter than a bit width of the partial bit field; an access key retaining unit which retains a plurality of access keys to control access to a memory from peripheral devices in association with each of the peripheral devices; and an indexing unit which indexes the access keys from the access key retaining unit using an index address including the reduced bit field if the conversion of the partial bit field into the reduced bit field is successful, and indexes the access keys from the access key retaining unit using an index address including the partial bit field if the conversion of the partial bit field into the reduced bit field is unsuccessful.
3 Citations
7 Claims
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1. An access key generating apparatus comprising:
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a bit field converting unit which converts a partial bit field, as a portion of a bit field indicating a device identifier of peripheral devices, into a reduced bit field having a bit width shorter than a bit width of the partial bit field; an access key retaining unit which retains a plurality of access keys to control access to a memory from the peripheral devices in association with each of the peripheral devices; and an indexing unit which indexes the access keys from the access key retaining unit using an index address including the reduced bit field if the conversion of the partial bit field into the reduced bit field is successful, and indexes the access keys from the access key retaining unit using an index address including the partial bit field if the conversion of the partial bit field into the reduced bit field is unsuccessful.
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2. An access key generating apparatus comprising:
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a bus number converting unit which converts a bus number, as a portion of a bit field indicating a device identifier of peripheral devices, into a reduced bus number having a bit width shorter than a bit width of the bus number; an access key retaining unit which retains a plurality of access keys to control access to a memory from the peripheral devices in association with each of the peripheral devices; and an indexing unit which indexes the access keys from the access key retaining unit using an index address including the reduced bus number if the conversion of the bus number into the reduced bus number is successful, and indexes the access keys from the access key retaining unit using an index address including the bus number if the conversion of the bus number into the reduced bus number is unsuccessful. - View Dependent Claims (3, 4, 5)
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6. An information processing apparatus comprising:
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a bit field converting unit which converts a partial bit field, as a portion of a bit field indicating a device identifier of peripheral devices, into a reduced bit field having a bit width shorter than a bit width of the partial bit field; an access key retaining unit which retains a plurality of access keys to control access to a memory from the peripheral devices in association with each of the peripheral devices; an indexing unit which indexes the access keys from the access key retaining unit using an index address including the reduced bit field if the conversion of the partial bit field into the reduced bit field is successful, and indexes the access keys from the access key retaining unit using an index address including the partial bit field if the conversion of the partial bit field into the reduced bit field is unsuccessful; and a memory access control unit which uses the indexed access keys to control access to the memory.
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7. An information processing apparatus comprising:
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a bus number converting unit which converts a bus number, as a portion of a bit field indicating a device identifier of peripheral devices, into a reduced bus number having a bit width shorter than a bit width of the bus number; an access key retaining unit which retains a plurality of access keys to control access to a memory from the peripheral devices in association with each of the peripheral devices; an indexing unit which indexes the access keys from the access key retaining unit using an index address including the reduced bus number if the conversion of the bus number into the reduced bus number is successful, and indexes the access keys from the access key retaining unit using an index address including the bus number if the conversion of the bus number into the reduced bus number is unsuccessful; and a memory access control unit which uses the indexed access keys to control access to the memory.
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Specification