Datasheet

4-8 MCF5307 User’s Manual
Cache Organization
Figure 4-3. Cache Organization and Line Format
A set is a group of four lines (one from each level, or way), corresponding to the same index
into the cache array.
4.8.1 Cache Line States: Invalid, Valid-Unmodified, and
Valid-Modified
As shown in Table 4-3, a cache line can be invalid, valid-unmodified (often called
exclusive), or valid-modified.
A valid line can be explicitly invalidated by executing a CPUSHL instruction.
Table 4-3. Valid and Modified Bit Settings
V M Description
0 x Invalid. Invalid lines are ignored during lookups.
1 0 Valid, unmodified. Cache line has valid data that matches system memory.
1 1 Valid, modified. Cache line contains most recent data, data at system memory location is stale.
Way 0 Way 1 Way 2 Way 3
Line
Set 0
Set 1
Set 126
Set 127
•
•
•
•
•
•
•
•
•
•
•
•
TAG V M Longword 0 Longword 1 Longword 2 Longword 3
Where:
TAG—21-bit address tag
V—Valid bit for line
M—Modified bit for line
Cache Line Format
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