
Data Cache Signals
Copyright 2000–2001 by LSI Logic Corporation. All rights reserved.
2-19
DSet0We0U, DSet1We0U, DSet2We0U, DSet3We0U
Data Set 0, 1, 2, 3 Write Enable Byte 0, UpperOutput
Asserting this signal HIGH enables writing to data
bits [7:0] in the Upper RAM of data set 0, 1, 2, or 3.
DSet0We1U, DSet1We1U, DSet2We1U, DSet3We1U
Data Set 0, 1, 2, 3 Write Enable Byte 1, UpperOutput
Asserting this signal HIGH enables writing to data
bits [15:8] in the Upper RAM of data set 0, 1, 2, or 3.
DSet0We2U, DSet1We2U, DSet2We2U, DSet3We2U
Data Set 0, 1, 2, 3 Write Enable Byte 2, UpperOutput
Asserting this signal HIGH enables writing to data
bits [23:16] in the Upper RAM of data set 0, 1, 2, or 3.
DSet0We3U, DSet1We3U, DSet2We3U, DSet3We3U
Data Set 0, 1, 2, 3 Write Enable Byte 3, UpperOutput
Asserting this signal HIGH enables writing to data
bits [31:24] in the Upper RAM of data set 0, 1, 2, or 3.
DTagAdrs[12:0]
Data Cache Tag Address
This bus contains the address for the data tag RAMs.
Output
DTagData[21:0]
Data Cache Tag Data
This bus contains data to be written to the data tag
RAMs.
Output
DTagSet0En, DTagSet1En, DTagSet2En, DTagSet3En,
Data Set 0, 1, 2, 3 Tag Enable
Driving this signal HIGH enables the clock on the Set 0,
1, 2, or 3 Tag RAM. Driving it LOW disables the clock,
which saves power. The RAMs do not have to connect to
this pin. The function is not changed if the RAMs ignore
the enable and clock every cycle.
Output
DTagSet0We, DTagSet1We, DTagSet2We, DTagSet3We,
Data Set 0, 1, 2, 3 Tag Write Enable
Asserting this signal HIGH enables writing to the Set 0,
1, 2, or 3 Tag RAM.
Output
DValid[3:0]
Data Cache Valid Bits
These bits are the data cache valid bits. There is one
valid bit for each data cache set. Individual valid bits are
selected by the index portion of the cache address.
Input