10. CACHE Instructions

10.15 Hit Writeback Invalidate (D)

Hit Writeback Invalidate (D) invalidates an entry in the primary data cache which matches the PA of the CACHE instruction. In addition, it writes back to the secondary cache any DirtyExclusive or Inconsistent data found in the primary data cache. Both way DTags at VA[13:5] are read from the data cache.

If the DState is not equal to 00 (Invalid) and PA of the CACHE instruction matches the DTag, then the DState bits of the entry are set to 00 (Invalid), the SCWay is set to 0, the DState parity is set to 0, and the StateMod bits are set to 0012 (Normal).

The LRU bit is left unchanged.

If the state of the block to be invalidated was found to be StateMod = 0102 (Inconsistent), the block in the primary data cache must be written back to the secondary cache. The address and way in the secondary cache to be written back to are read out of the primary data cache Tag Address and secondary way fields, and all 32 bytes are written back.

Only the data field of the secondary cache is modified by this instruction since the processor obeys State and data subset rules.

Since the CE bit is not defined in the R10000 processor, this instruction no longer has an ECC register mode.

Hit CacheOps can cause cache error exceptions if they check ECC or parity bits.

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