5.3 Secondary Cache Indexing
Indexing the Data Array
Since the maximum secondary cache size is 16 Mbytes (8 Mbytes per way), each way requires a maximum of 23 bits to index a byte within a selected way, or 19 bits to index a quadword within a way. Consequently, the processor supplies PA(22:4) on SC(A,B)Addr(18:0) to index a quadword within a way. The processor selects a secondary cache data way with the SC(A,B)DWay signal.
Table 5-1 presents the secondary cache data array index for each secondary cache size; for instance, a 4 Mbyte cache uses the 17 address bits, PA(20:4) on SC(A,B)Addr(16:0), concatenated with the way bit, SC(A,B)DWay, to index a quadword within a 2 Mbyte way.
Table 5-1 Secondary Cache Data Array Index
Copyright 1995, MIPS Technologies, Inc. -- 29 JAN 96
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