EP0260433A2 — Multi-address space control method

Claim 1

Independent Claim 215 words

An information processing method including accessing a plurality of address spaces (19, 22) produced by different address translation tables (9) based on a selection command (7) for a plurality of leading address registers (5, 6), and comparing (12) a program status word (PSW) key (P k , 1) with a main storage key (M k , 11) to thereby protect a main memory, comprising, in a data transfer between different access spaces, the stpes of: (a) setting a work access key (W k ) capable of being designated in accordance with an instruction to be executed, independently from said program status word key; (b) selecting as an access key (K) on the side of a central processing unit one of said program status word (PSW) key (P k ) and said work access key (W k ); (c) if the selected access key is at a predetermined value (K=0), allowing an access to said main storage irrespective of said main storage key value; and (d) accessing different address spaces by changing said plurality of leading address registers, PSW key (P k ) and word access key (W k ), detecting an access exception, and if an access exception is not detected, setting said predetermined value (K=0) as an access key in said work access key.

Claim 2

Dependent Claim 215 words

An information processing method including accessing a plurality of address spaces (19, 22) produced by different address translation tables (9) based on a selection command (7) for a plurality of leading address registers (5, 6), and comparing (12) a program status word (PSW) key (P k , 1) with a main storage key (M k , 11) to thereby protect a main memory, comprising, in a data transfer between different access spaces, the stpes of: (a) setting a work access key (W k ) capable of being designated in accordance with an instruction to be executed, independently from said program status word key; (b) selecting as an access key (K) on the side of a central processing unit one of said program status word (PSW) key (P k ) and said work access key (W k ); (c) if the selected access key is at a predetermined value (K=0), allowing an access to said main storage irrespective of said main storage key value; and (d) accessing different address spaces by changing said plurality of leading address registers, PSW key (P k ) and word access key (W k ), detecting an access exception, and if an access exception is not detected, setting said predetermined value (K=0) as an access key in said work access key.

Claim 3

Dependent Claim 37 words

A method according to claim 1, wherein each of said steps is executed under control of microprograms, said steps constituting a pre-testing (rehearsal) for setting an access key to be prepared on the central processing unit side.

Claim 4

Dependent Claim 25 words

A method according to claim 1, wherein said access exception includes translation specification exception, segment translation exception, page translation exception, addressing exception, and protection exception.

Claim 5

Dependent Claim 21 words

A method according to claim 1, wherein said step (c) includes a step of inhibiting actual accessing to said main storage.

Claim 6

Dependent Claim 38 words

A method according to claim 2, wherein said step (d) includes a store rehearsal for an address space to which a data is transferred and a fetch rehearsal for an address space from which a data is transferred.

Claim 7

Dependent Claim 229 words

An information processing system wherein a plurality of address spaces (19, 22) produced by different address translation tables based on a selection command for a plurality of leading address registers (5, 6) are accessed, and a program status word key (P k ) and a storage key (M k ) are compared to protect a main storage, having a multi-address space control system comprising: a first key register (1) for holding said program status word key; a second key register (2) for holding a work access key variably designated in accordance with an instruction to be executed; a key selector (3) for selecting said first and second key registers; judging means (4) coupled to the output of said key selector (3) for judging whether the value of key selected from said first and second key registers is a predetermined value (K=0), and enabling an access to said main storage irrespective of the value of said storage key if said selected key value is equal to said predetermined value; an means (12, 16, 4, 3, 2) for accessing different address spaces by changing said plurality of leading address registers, and said first and second key registers, detecting an access exception, and setting, if an access exception is not detected, said predetermined value in said second key register as an access key for use in transferring data between different address spaces.

Claim 8

Dependent Claim 229 words

An information processing system wherein a plurality of address spaces (19, 22) produced by different address translation tables based on a selection command for a plurality of leading address registers (5, 6) are accessed, and a program status word key (P k ) and a storage key (M k ) are compared to protect a main storage, having a multi-address space control system comprising: a first key register (1) for holding said program status word key; a second key register (2) for holding a work access key variably designated in accordance with an instruction to be executed; a key selector (3) for selecting said first and second key registers; judging means (4) coupled to the output of said key selector (3) for judging whether the value of key selected from said first and second key registers is a predetermined value (K=0), and enabling an access to said main storage irrespective of the value of said storage key if said selected key value is equal to said predetermined value; an means (12, 16, 4, 3, 2) for accessing different address spaces by changing said plurality of leading address registers, and said first and second key registers, detecting an access exception, and setting, if an access exception is not detected, said predetermined value in said second key register as an access key for use in transferring data between different address spaces.

Claim 9

Dependent Claim 215 words

An information processing system for a multi-address space control wherein when a main storage is to be accessed from a central processing unit, a main storage protection is conducted by comparing an access key prepared in said central processing unit with a main storage key provided in the main storage, comprising: a first key register (1) for storing a program status word key prepared in said central processing unit; a second key register (2) for storing an access key designated in accordance with a data transfer instruction; a selector (3) for selecting one of the outputs from said first and second key registers; judging means (4) coupled to said selector for comparing a key value from a selected key register with a predetermined value, allowing an access to said main storage irrespective of said main storage key when the key value of said selected key register matches said predetermined value, and making the key value of said selected key register to be compared with said main storage key; and means including a microprogram for executing a predetermined procedure, for setting said predetermined value in said second key register as an access key for data transfer between a plurality of address spaces when a key included in a transfer instruction coincides with said main storage key.

Claim 10

Dependent Claim 215 words

An information processing system for a multi-address space control wherein when a main storage is to be accessed from a central processing unit, a main storage protection is conducted by comparing an access key prepared in said central processing unit with a main storage key provided in the main storage, comprising: a first key register (1) for storing a program status word key prepared in said central processing unit; a second key register (2) for storing an access key designated in accordance with a data transfer instruction; a selector (3) for selecting one of the outputs from said first and second key registers; judging means (4) coupled to said selector for comparing a key value from a selected key register with a predetermined value, allowing an access to said main storage irrespective of said main storage key when the key value of said selected key register matches said predetermined value, and making the key value of said selected key register to be compared with said main storage key; and means including a microprogram for executing a predetermined procedure, for setting said predetermined value in said second key register as an access key for data transfer between a plurality of address spaces when a key included in a transfer instruction coincides with said main storage key.

Claim 11

Dependent Claim 73 words

A system according to Claim 6, wherein said instruction is a data transfer instruction, one of first and second operands is fetched and stored into the other operand address, the access key (P k ) for said one of first and second operands is designated by said program status instruction and the access key (W k ) for the other of the first and second operands is designated by said data transfer instruction.

Claim 12

Dependent Claim 34 words

A system according to Claim 8, wherein said key selector (3) selects one of the outputs of said first and second key registers (1, 2) by a microprogram associated with said data transfer instruction.

Claim 13

Dependent Claim 61 words

A system according to Claim 6, wherein said first key register (1) holds an access key to detect an access exception for one of first and second operands and said second key register (2) holds a key given by a data transfer instruction as an access key to detect an access exception for the other of said first and second operands.

Claim 14

Dependent Claim 40 words

A system according to Claim 6, wherein said second key register (2) is set at a key value always available to access for transfer of first and second operands of a predetermined unit length through repetitive fetch and store operations.

Multi-address space control method

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