Concurrent context memory management unit

Claim 2

A memory management unit (10) for use in controlling data storage and retrieval from a memory (12), said unit operable for translating between virtual addresses received in response to storage or retrieval instructions and physical addresses within said memory, said instructions receivable from a plurality of different sources, each source having the same virtual address mapped to a different physical address, said unit comprising means (404) for storing translation information for said plurality of different sources for each mapped virtual-to-physical address pair of each said source, means (103, 104, 105) for selectively controlling for any presented instruction which one of the stored virtual-to-physical address mappings will be utilized by said unit to perform said translation, and means (106) for enabling said selective controlling means from mode information associated with each received virtual address.

Claim 3

The unit set forth in claim 1 wherein said unit is interposed between a central processing unit (CPU) (11) and its main memory (12) and wherein said instructions are received from said CPU, and wherein said plurality of sources includes a plurality of processes (201, 202, 203) operating within said CPU.

Claim 4

The unit set forth in claim 1 wherein said enabling means includes means (103, 106) for establishing a default selection in the absence of receipt of said mode information accompanying said received instructions.

Claim 5

The unit set forth in claim 1 wherein said enabling means includes means (103, 106) for selecting a particular one of said stored mappings without regard to said mode information accompanying said received instructions.

Claim 8

The method set forth in claim 5 wherein said virtual addresses each may have several physical addresses and wherein said method further comprises the step of selecting, in lieu of receipt of said control information, a particular one of said stored plurality of physical addresses associated with said particular virtual address.

Claim 9

In a system having a memory management unit (MMU) (10) interposed between a plurality of sources of virtual addresses and a memory (12) having physical locations to which the virtual addresses are periodically mapped, and wherein the same virtual address from different sources may be mapped to the same physical location within said memory, and wherein said MMU contains a first index (103) for controlling the storage or retrieval of information to or from said memory in response to a virtual address presented to said MMU, said first index temporarily associated with said MMU depending upon the source of said presented virtual addresses, the improvement comprising means for storing within said MMU at least one other index (104, 105) associated with a second source of virtual addresses while said first index associated with a first source of virtual addresses is stored within said MMU, and means operative in response to information associated with each said presented virtual address for selecting one or the other of said first or other indices for controlling said translation between a presented virtual address and the associated physical address.

Claim 10

In a system having a memory management unit (MMU) (10) interposed between a plurality of sources of virtual addresses and a memory (12) having physical locations to which the virtual addresses are periodically mapped, and wherein the same virtual address from different sources may be mapped to the same physical location within said memory, and wherein said MMU contains a first index (103) for controlling the storage or retrieval of information to or from said memory in response to a virtual address presented to said MMU, said first index temporarily associated with said MMU depending upon the source of said presented virtual addresses, the improvement comprising means for storing within said MMU at least one other index (104, 105) associated with a second source of virtual addresses while said first index associated with a first source of virtual addresses is stored within said MMU, and means operative in response to information associated with each said presented virtual address for selecting one or the other of said first or other indices for controlling said translation between a presented virtual address and the associated physical address.

Claim 11

The improvement set forth in claim 7 wherein said improvement further comprises means (106) for establishing one or the other of said first or other indices as a default index, said default index operative in the absence of said associated information for controlling said translation between a presented virtual address and the associated physical address without regard to the source of said virtual address.

Claim 12

The improvement set forth in claim 8 wherein said virtual address is presented in a data packet having address bits, and read, write, and execute bits, and wherein said selecting means includes at least one register operative in response to said read, write and execute bits.

Claim 13

The improvement set forth in claim 9 wherein said selecting means includes a plurality of registers and said establishing means is further operative to inhibit a subset of said registers thereby controlling said translation between a presented virtual address and the associated physical address without regard to the source of said virtual address.