Fujitsu Fujitsu SPARC64 V Handling of an I1 Cache Data Error, Handling of a D1 Cache Data Error

Models: Fujitsu SPARC64 V

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P.9.2 Handling of an I1 Cache Data Error

I1 cache data is protected by parity attached to every doubleword.

When a parity error is detected in I1 cache data during an instruction fetch, hardware executes the following sequence:

1.Reread the I1 cache line containing the parity error from the U2 cache.

The read data from U2 cache must contain only the doubleword without error or the doubleword with the marked UE, because error marking is applied to U2 cache outgoing data.

2.For each doubleword read from U2 cache:

a.When the doubleword does not have a UE, save the correct data in the I1 cache doubleword without parity error and supply the data for instruction fetch if required.

There is no direct report to software for an I1 cache error corrected by refilling data.

b.When the doubleword has a marked UE, set the parity bit in the I1 cache doubleword to indicate a parity error and supply the parity error data for the instruction fetch if required.

3.Treat a fetched instruction with an error as follows:

When the instruction with a parity error is fetched but not executed in any way visible to software, the fetched instruction with the error is discarded.

Otherwise, fetch and execute the instruction with the indicated parity error. When the execution of the instruction is complete, an

exception will be generated (precise trap), and the marked UE detection and its ERROR_MARK_ID will be indicated in ASI_ISFSR.

P.9.3 Handling of a D1 Cache Data Error

D1 cache data is protected by 2-bit error detection and 1-bit error correction ECC, attached to every doubleword.

Correctable Error in D1 Cache Data

When a correctable error is detected in D1 cache data, the data is corrected automatically by hardware. There is no direct report to software for a D1 cache correctable error.

190 SPARC JPS1 Implementation Supplement: Fujitsu SPARC64 V • Release 1.0, 1 July 2002

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Fujitsu Fujitsu SPARC64 V manual Handling of an I1 Cache Data Error, Handling of a D1 Cache Data Error