Shared memory multiprocessor with data hiding and post-store
First Claim
1. A digital data processing system comprisingA. plural processing cells, each comprising a central processing unit and an associated memory element for storing information-representative signals, said plural memory elements together forming a common memory,B. each said central processing unit including access request means for generating an access-request signal representative of a request for access to an information-representative signal stored in said common memory, andC. each said processing cell including memory management means, coupled to the corresponding central processing unit and memory element of that processing cell, for selectively responding to an access-request signal for at least signaling the availability of an information-representative signal stored in that corresponding memory element,the memory management means of respective processing cells being coupled to one another for selective transfer of access-request signals therebetween,D. each said memory management means including directory means for storing an ANCHOR signal corresponding to each of at least selected information-representative signals in the corresponding memory element, said ANCHOR signal being indicative of a mode by which the corresponding information-representative signal is accessible,E. said memory management means including means for responding to an access-request signal generated by any of said central processing units directed to an information-representative signal having an ANCHOR signal indicative of a first alternative mode of access for at least signaling the requesting central processing unit that the requested information-representative signal is stored in said common memory, andF. said memory management means including means for responding to an access-request signali) generated by the central processing unit corresponding to that memory management means and directed to an information-representative signal stored within the corresponding memory element, which information-representative signal is associated with an ANCHOR signal indicative of a second alternative mode of access, for signaling that corresponding central processing unit that the requested information-representative signal is stored in said common memory, andii) generated by any other of said central processing units directed to that same information-representative signal for signaling the requesting central processing unit that the requested information-representative signal is not stored in said common memory.
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Abstract
A digital data processing system includes a plurality of central processor units which share and access a common memory through a memory management element. The memory management element permits, inter alia, data in the common memory to be accessed in at least two modes. In the first mode, all central processing units requesting access to a given datum residing in memory are signalled of the datum'"'"'s existence. In the second mode, only selected central processing units requesting access to a resident datum are notified that it exists, while others requesting access to the datum are signalled that it does not exist. The common memory can include a plurality of independent memory elements, each coupled to and associated with, a respective one of the central processing units. A central processing unit can include a post-store element for effecting the transfer of copies of data stored in its associated memory element to a memory element associated with another central processing unit.
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Citations
20 Claims
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1. A digital data processing system comprising
A. plural processing cells, each comprising a central processing unit and an associated memory element for storing information-representative signals, said plural memory elements together forming a common memory, B. each said central processing unit including access request means for generating an access-request signal representative of a request for access to an information-representative signal stored in said common memory, and C. each said processing cell including memory management means, coupled to the corresponding central processing unit and memory element of that processing cell, for selectively responding to an access-request signal for at least signaling the availability of an information-representative signal stored in that corresponding memory element, the memory management means of respective processing cells being coupled to one another for selective transfer of access-request signals therebetween, D. each said memory management means including directory means for storing an ANCHOR signal corresponding to each of at least selected information-representative signals in the corresponding memory element, said ANCHOR signal being indicative of a mode by which the corresponding information-representative signal is accessible, E. said memory management means including means for responding to an access-request signal generated by any of said central processing units directed to an information-representative signal having an ANCHOR signal indicative of a first alternative mode of access for at least signaling the requesting central processing unit that the requested information-representative signal is stored in said common memory, and F. said memory management means including means for responding to an access-request signal i) generated by the central processing unit corresponding to that memory management means and directed to an information-representative signal stored within the corresponding memory element, which information-representative signal is associated with an ANCHOR signal indicative of a second alternative mode of access, for signaling that corresponding central processing unit that the requested information-representative signal is stored in said common memory, and ii) generated by any other of said central processing units directed to that same information-representative signal for signaling the requesting central processing unit that the requested information-representative signal is not stored in said common memory.
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10. A digital data processing system comprising
A. plural processing cells, each including a central processing unit coupled to an associated memory element, each said memory element being capable of storing one or more information-representative signals, B. memory management means coupled to said plural memory elements for accessing one or more information-representative signals stored in said plural memory elements, C. at least a first central processing unit including means for generating a request for priority access to a selected information-representative signal for which physical storage space is allocated in the memory element associated with another central processing unit, D. said memory management means including means responsive to such request for i) allocating, within the memory element associated with the first central processing unit, physical storage space for said selected information-representative signal, and for storing that signal therein, and ii) invalidating copies of said selected information-representative signal, if any, stored in said physical storage space allocated to that information-representative signal in said other memory elements, E. said first central processing unit including means for generating a POST-STORE signal representative of a request for transfer of a copy of said selected information-representative signal to other memory elements having space allocated to that information-representative signal, and F. said memory management means including means responsive to such POST-STORE signal for transferring and storing a copy of said selected information-representative signal to the other processing cells having physical storage space allocated for said selected information-representative signal in the memory elements thereof.
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13. A method of operating a digital data processing system comprising
A. providing plural processing cells, each comprising a central processing unit and an associated memory element for storing information-representative signals, wherein said plural memory elements together form a common memory, B. storing, within each said processing cells, ANCHOR signals indicative of a mode by which each of at least selected information-representative signals is accessible, C. generating, within any of said central processing units, an access-request signal representative of a request for access to an information-representative signal stored in said common memory, and D. responding, within each of said processing cells, to an access-request signal generated by any of said central processing units directed to an information-representative signal having an ANCHOR signal indicative of a first alternative mode of access for signaling the requesting central processing unit that the requested information-representative signal is stored in said common memory, and E. responding, within a processing cell, to an access-request signal generated by the central processing unit of that cell directed to an information-representative signal stored in the memory element of that cell and having access for signaling that central processing unit that the requested information-representative signal is stored in said common memory, and responding to an access-request signal generated by any other of said central processing units directed to that same information-representative signal for signaling the requesting central processing unit that the requested information-representative signal is not stored in said common memory.
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18. A method for operating a multiprocessor digital data comprising
A. providing plural processing cells, each including a central processing unit coupled to an associated memory element, each said memory element being capable of storing one or more information-representative signals, B. generating, within at least a first one of said central processing units, a request for priority access to a selected information-representative signal, said selected information-representative signal being one for which physical storage space is allocated in another of said memory elements, C. responding to said ownership-request signal for i) allocating within the memory element associated with the first central processing unit, physical storage space for said selected information-representative signal, and for storing that signal therein, ii) invalidating an information-representative signal stored in the physical storage space allocated to said selected information-representative signal in said other memory element, D. generating, within said first central processing unit, a post-store signal representative of a request for transfer of a copy of said information-representative signal to said other memory elements, and E. responding to said post-store signal for transferring a copy of said selected information-representative signal to said other processing cells for storage in the physical storage space allocated for said selected information-representative signal in said other memory elements.
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19. A digital data processing system comprising
A. plural processing cells, each including a central processing unit coupled to an associated memory element, each said memory element being capable of storing one or more information-representative signals, B. memory management means coupled to said plural memory elements for accessing one or more information-representative signals stored in said plural memory elements, C. at least a first central processing unit including means for executing an ownership-access instruction for generating a request for priority access to a selected information-representative signal for which physical storage space is allocated in the memory element associated with another central processing unit, D. said memory management means including means responsive to such request for i) allocating, within the memory element associated with the first central processing unit, physical storage space for said selected information-representative signal, and for storing that signal therein, and ii) invalidating copies of said selected information-representative signal, if any, stored in said physical storage space allocated to that information-representative signal in said other memory elements, E. said first central processing unit including means for executing a POST-STORE instruction for generating a POST-STORE signal representative of a request for transfer of a copy of said selected information-representative signal to other memory elements having space allocated to that information-representative signal, and F. said memory management means including means responsive to such POST-STORE signal for transferring and storing a copy of said selected information-representative signal to the other processing cells having physical storage space allocated for said selected information-representative signal in the memory elements thereof.
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20. A method for operating a multiprocessor digital data comprising
A. providing plural processing cells, each including a central processing unit coupled to an associated memory element, each said memory element being capable of storing one or more information-representative signals, B. executing, with at least a first one of said central processing units, an ownership-access instruction for generating a request for priority access to a selected information-representative signal, said selected information-representative signal being one for which physical storage space is allocated in another of said memory elements, C. responding to said ownership-request signal for i) allocating within the memory element associated with the first central processing unit, physical storage space for said selected information-representative signal, and for storing that signal therein, ii) invalidating an information-representative signal stored in the physical storage space allocated to said selected information-representative signal in said other memory element, D. executing, with said first central processing unit, a POST-STORE instruction for generating a POST-STORE signal representative of a request for transfer of a copy of said information-representative signal to said other memory elements, and E. responding to said POST-STORE signal for transferring a copy of said selected information-representative signal to said other processing cells for storage in the physical storage space allocated for said selected information-representative signal in said other memory elements.
Specification