Bus arbiter method and system

Claim 2

An improved bus arbitration system, comprising: an information bus; a first bus master connected to said information bus, said first bus master adapted to speculatively pre-fetch and having a first REQ signal for requesting ownership of said bus and an SP signal for indicating a speculative pre-fetch operation; a second bus master connected to said information bus and having a second REQ signal for requesting ownership of said bus; and a bus arbiter adapted to receive said first REQ signal, said second REQ signal, and said SP signal and wherein said bus arbiter is configured to assign said second bus master higher bus request priority than said first bus master in response to said SP signal when said first REQ signal, said second REQ signal, and said SP signal have been asserted.

Claim 3

The bus arbitration system of claim 1 wherein said bus arbiter further comprises first and second GNT signals routed to said first and second bus masters for indicating permission to take ownership of said bus in response to said first and second REQ signals.

Claim 4

The bus arbitration system of claim 1 wherein said bus arbiter further comprises a BOFF signal routed to said first and second bus masters for withdrawing ownership of said bus from said first and second bus masters.

Claim 5

The bus arbitration system of claim 3 wherein said bus arbiter is further configured to assert said BOFF signal when said second REQ signal is asserted while said first bus master has ownership of said bus and said first bus master is speculatively pre-fetching.

Claim 6

The bus arbitration system of claim 1 wherein said first and second bus masters comprise first and second central processing units.

Claim 7

The bus arbitration system of claim 1 wherein said information bus comprises a PCI local bus.

Claim 8

An improved bus arbitration system of the type having first and second bus masters connected to said bus and a bus arbiter for controlling ownership of said bus, each said first and second bus masters having a bus ownership request signal routed to said bus arbiter, said bus arbiter having first and second bus ownership grant signals routed to said first and second bus masters respectively for indicating ownership of said bus in response to said bus ownership request signal, said first bus master requesting ownership of said bus to perform a speculative pre-fetch information transfer and said second bus master requesting ownership of said bus to perform a non-speculative information transfer, wherein the improvement comprises: a speculative pre-fetch signal generated by said first bus master and routed to said bus arbiter, said speculative pre-fetch signal indicating whether said master is requesting ownership of said bus to perform speculative pre-fetch data transfers; and wherein said bus arbiter is configured to assign said first bus ownership request lower priority than said second bus ownership request signal in response to said speculative pre-fetch signal.

Claim 9

An improved bus arbitration system of the type having first and second bus masters connected to said bus and a bus arbiter for controlling ownership of said bus, each said first and second bus masters having a bus ownership request signal routed to said bus arbiter, said bus arbiter having first and second bus ownership grant signals routed to said first and second bus masters respectively for indicating ownership of said bus in response to said bus ownership request signal, said first bus master requesting ownership of said bus to perform a speculative pre-fetch information transfer and said second bus master requesting ownership of said bus to perform a non-speculative information transfer, wherein the improvement comprises: a speculative pre-fetch signal generated by said first bus master and routed to said bus arbiter, said speculative pre-fetch signal indicating whether said master is requesting ownership of said bus to perform speculative pre-fetch data transfers; and wherein said bus arbiter is configured to assign said first bus ownership request lower priority than said second bus ownership request signal in response to said speculative pre-fetch signal.

Claim 10

The system of claim 7 wherein said first bus master comprises a first central processing unit.

Claim 11

The system of claim 8 further comprising one or more additional central processing units connected to said bus wherein each said additional processing unit is connected to said bus, each said additional central additional processing unit having a bus ownership request signal routed to said bus arbiter and a bus grant signal from said bus arbiter.

Claim 12

The system of claim 7 wherein said bus arbiter is further configured to backoff a bus ownership grant for a speculative pre-fetch in response to a subsequent non-speculative bus ownership request.

Claim 15

The method of claim 11 wherein said first bus master's request and said speculative pre-fetch signal are asserted simultaneously.

Claim 16

The method of claim 11 wherein said first and second bus masters comprise central processing units.

Claim 17

The method of claim 11 further comprising the step of granting ownership of said bus to said second bus master in response to said second request.

Claim 18

The method of claim 11 wherein said information bus comprises a PCI bus.