Large logical addressing method and means

Claim 1

A method of address translating large size virtual addresses (LVAs) for locating data and instructions a computer memory, comprising: indexing a highest-order part (ADEN) of an LVA into an access directory (AD) for selecting an AD entry (ADE), and accessing a cumulative offset field (LVAS-CO) and an access list origin (ALO) in the selected ADE; accessing an access list (AL) with the ALO, and indexing higher-order part (ALEN) of the LVA into the accessed AL to select an access list entry (ALE), said ALE representing a conventional virtual address sub-space in a large virtual address space; adding a value in the cumulative offset field (LVAS-CO) to a concatenation of the ADEN and ALEN fields in the LVA to obtain an effective LVA having a highest-order effective ADEN and a higher-order effective ALEN; comparing the highest-order effective ADEN to the ADEN in the LVA; using a last selected ADE selected by the last highest-order effective ADEN as a correct ADE if a compare equal condition is found by the comparing step; accessing a next ADE in the AD by incrementing the value of the current highest-order effective ADEN if the comparing step finds an unequal condition, and accessing a next LVAS-CO in the next ADE; and repeating the adding, comparing, using, and accessing a next ADE steps until a compare equal condition is found, said compare equal condition indicating the last effective highest-order ADEN provided by the adding step is to be used for locating a required AL, and a last effective higher-order ALEN provided by the adding step is to be used for locating an ALE in the required AL for accessing a conventional virtual address sub-space for completing the translation of the LVA to a real address.

Claim 2

A method of address translating large size virtual addresses (LVAs) for locating data and instructions a computer memory, comprising: indexing a highest-order part (ADEN) of an LVA into an access directory (AD) for selecting an AD entry (ADE), and accessing a cumulative offset field (LVAS-CO) and an access list origin (ALO) in the selected ADE; accessing an access list (AL) with the ALO, and indexing higher-order part (ALEN) of the LVA into the accessed AL to select an access list entry (ALE), said ALE representing a conventional virtual address sub-space in a large virtual address space; adding a value in the cumulative offset field (LVAS-CO) to a concatenation of the ADEN and ALEN fields in the LVA to obtain an effective LVA having a highest-order effective ADEN and a higher-order effective ALEN; comparing the highest-order effective ADEN to the ADEN in the LVA; using a last selected ADE selected by the last highest-order effective ADEN as a correct ADE if a compare equal condition is found by the comparing step; accessing a next ADE in the AD by incrementing the value of the current highest-order effective ADEN if the comparing step finds an unequal condition, and accessing a next LVAS-CO in the next ADE; and repeating the adding, comparing, using, and accessing a next ADE steps until a compare equal condition is found, said compare equal condition indicating the last effective highest-order ADEN provided by the adding step is to be used for locating a required AL, and a last effective higher-order ALEN provided by the adding step is to be used for locating an ALE in the required AL for accessing a conventional virtual address sub-space for completing the translation of the LVA to a real address.

Claim 3

A method of address translating large size virtual addresses (LVAs) being used by programs executing in a computer system, comprising the steps of: adding a content of an index register (X) to a content of a large base register (B) and a displacement (D) to generate at least a low-order part and a high-order part of a LVA, the low-order part having a size equal to a conventional virtual address (CVA), and the high-order part including an access list entry number (ALEN), said ALEN being utilized to locate a selected access list entry (ALE) from a plurality of ALEs, the ALEs representing different virtual sub-spaces in a large virtual address space (LVAS) addressed by the LVA, said LVA having more bits than found in a CVA; incrementing the high-order part represented by the ALEN when a carry signal is generated during the generation of the low-order part, said incrementing changing the ALEN, causing it change in the selection of an ALE, and a resulting change in the selection of a virtual sub-space in the LVAS; structuring the LVAS with a virtual address space granularity determined by the ALEs which define virtual sub-space granular units of the LVAS equal to the size of a conventional virtual address space (CVAS), said virtual sub-spaces having a size equal to the number of bytes equal to 2 to the power of the number of bits in a CVA; locating an access list (AL) in system memory at a location determined by an access list entry Origin (ALO); and selecting an ALE by indexing the ALEN into the AL, the selected ALE containing an address for locating an associated virtual address translation table for translating the LVA to a real address by translating the low-order part of the LVA to a real address, such that an address is accessed in the virtual sub-space defined by the selected ALE.

Claim 4

A method of address translating large size virtual addresses (LVAs) being used by programs executing in a computer system, comprising the steps of: adding a content of an index register (X) to a content of a large base register (B) and a displacement (D) to generate at least a low-order part and a high-order part of a LVA, the low-order part having a size equal to a conventional virtual address (CVA), and the high-order part including an access list entry number (ALEN), said ALEN being utilized to locate a selected access list entry (ALE) from a plurality of ALEs, the ALEs representing different virtual sub-spaces in a large virtual address space (LVAS) addressed by the LVA, said LVA having more bits than found in a CVA; incrementing the high-order part represented by the ALEN when a carry signal is generated during the generation of the low-order part, said incrementing changing the ALEN, causing it change in the selection of an ALE, and a resulting change in the selection of a virtual sub-space in the LVAS; structuring the LVAS with a virtual address space granularity determined by the ALEs which define virtual sub-space granular units of the LVAS equal to the size of a conventional virtual address space (CVAS), said virtual sub-spaces having a size equal to the number of bytes equal to 2 to the power of the number of bits in a CVA; locating an access list (AL) in system memory at a location determined by an access list entry Origin (ALO); and selecting an ALE by indexing the ALEN into the AL, the selected ALE containing an address for locating an associated virtual address translation table for translating the LVA to a real address by translating the low-order part of the LVA to a real address, such that an address is accessed in the virtual sub-space defined by the selected ALE.