US 4,048,671 AGranted

Address match for data processing system with virtual addressing

AssigneeIBM Corporation

InventorsRobert William Callahan, Paul Eugene Kauffman, Matthew Joseph Mitchell, Jr.

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Abstract

Apparatus for signalling the occurrence of a match between an address that is supplied to a control store and an address that is to be watched for in a data processing system that executes several instruction streams concurrently. The apparatus signals the occurrence of a storage accessing operation at a location that is uniquely identified only by a virtual address that is longer than the actual address used in accessing the store. Means is provided for comparing the actual address used in accessing the store with the corresponding portion of the complete address, and means is provided for recording the location of an address to be watched for in a particular frame of the store and for signalling a match that occurs in such a frame. The apparatus is useful for testing the operation of the data processing system by relating a recurring malfunction of the system to the execution of an instruction at the address that is watched for.

Claims6

Dependent claims

Apparatus for detecting an address match in a data processing system having,

a store having a plurality of page frames and being accessible according to a first address having a page address portion and a word address portion, and
means for loading into a page frame of said store a page that is identified by a second address having a page address portion and a higher order bit portion, an address to be matched being uniquely identified by the combination of said second address and said word address portion of said first address,
wherein the improvement comprises,
means for holding the word portion of an address to be matched,
means connected to said means for holding the word portion of an address to be matched and connected to receive said word address portion of said first address for comparing the word portion of the address to be matched and said word portion of said first address and for producing a word address match signal,
a register having a bit position for each of said page frames of said store, each bit position of said register being adapted to be set to identify any page frame containing the page in which the word to be matched is located,
means for identifying a page frame being accessed in said store, and
means connected to receive said word address match signal and connected to each bit position of said register and to said means for identifying a page frame being accessed in said store for signalling an address match in response to the coincidence of said word address match signal and an operation to access a page frame for which a bit in said register has been set.

5 more elements

Dependencies are inferred from the claim text.