Detecting the occurrence of desired values on a bus

A system comprising:

• an addressable unit;
• processor;
• a bus transferring a present value between said addressable unit and said processor;
• a monitor memory containing a plurality of locations, each of said plurality of locations being addressed by a corresponding address, storing the bits at a second set of positions of each desired value at a location of a random access memory (RAM) having an address formed by the bits at a first set of positions of the desired value, wherein said first set of positions and said second set of positions are non-overlapping;
• and
• a comparator comparing an output of said monitor memory with an another input to generate a result,
• wherein bits at said first set of positions of said present value is provided as an address to said monitor memory to cause said monitor memory to provide the data stored at a location corresponding to said address as said output, wherein said location is comprised in said plurality of locations,
• wherein bits at said second set of positions of said present value is provided as said another input to said comparator,
• whereby said result indicates whether said present value equals at least one of said plurality of desired values.

A detection circuit for detecting the occurrence of a one of a plurality of desired values on a bus, each of said desired values containing N-bits, wherein N is a positive integer, said detection circuit comprising:

• means for storing the bits at a second set of positions of each desired value at a location of a random access memory (RAM) having an address formed by the bits of the desired value at a first set of positions;
• means for providing as an access address to said RAM, wherein said access address comprises the bits of said present value at said first set of positions, wherein said means for providing causes said RAM to generate an output;
• and
• means for comparing said output with an another input to generate a result, wherein said another input comprises the bits of said present value at said second set of positions,
• wherein said result indicates whether said present value matches one of said plurality of desired values.

A method of determining whether a present value matches one of a plurality of desired values, said method comprising:

• storing the bits at a second set of positions of each desired value at a location of a random access memory (RAM) having an address formed by the bits of the desired value at a first set of positions;
• providing an access address to said RAM, wherein said access address comprises the bits of said present value at said first set of positions, wherein said providing causes said RAM to generate an output;
• and
• comparing said output with an another input to generate a result, wherein said another input comprises the bits of said present value at said second set of positions,
• wherein said result indicates whether said present value matches one of said plurality of desired values.